Problem Analysis #0

86.16s
9,839 toks
Problem Statement

For positive integers a,b,ca,b,c we say that the triple (a,b,c)(a,b,c) is \emph{cyclically divisible} if

a+1b,b+1c,c+1a\frac{a+1}{b},\quad \frac{b+1}{c},\quad \frac{c+1}{a}

are all integers.

Let T\mathcal{T} be the set of all cyclically divisible ordered triples (a,b,c)(a,b,c) of positive integers. For any positive integer nn, define

S(a,b,c):=a+b+c,S(a,b,c):=a+b+c,

and the arithmetic function F:NNF:\mathbb{N}\to\mathbb{N} by

F(n):={(a,b,c)TS(a,b,c)n}.F(n):=\bigl|\{(a,b,c)\in\mathcal{T}\mid S(a,b,c)\mid n\}\bigr|.

For arithmetic functions u,v:NCu,v:\mathbb{N}\to\mathbb{C}, define their \emph{divisor-sum combination} by

(uv)(n):=dnu(d)v ⁣(nd)(nN),(u * v)(n):=\sum_{d\mid n}u(d)\,v\!\left(\frac{n}{d}\right)\qquad(n\in\mathbb{N}),

and let 1\mathbf{1} denote the constant function 1(n)1\mathbf{1}(n)\equiv 1.

It is known that the set T\mathcal{T} is finite. Moreover, there exists an arithmetic function

G:NZ0,G:\mathbb{N}\to\mathbb{Z}_{\ge 0},

depending only on the values of S(a,b,c)S(a,b,c) for (a,b,c)T(a,b,c)\in\mathcal{T}, such that

F(n)=(G1)(n)=dnG(d)for all nN.F(n) = (G * \mathbf{1})(n) = \sum_{d\mid n} G(d) \quad\text{for all } n\in\mathbb{N}.

Let

N:=107N:=10^7

and define the integer

K:=n=1N(n!)F(n).\mathcal{K} := \prod_{n=1}^{N} \bigl(n!\bigr)^{F(n)}.

Set

E:=v2(K),E := v_2(\mathcal{K}),

the exponent of 22 in the prime factorization of K\mathcal{K}.

Using the above information, determine the exact value of the integer EE.

Ground Truth
91666486036450
Execution Trace
Reasoning Process

[THOUGHT] I will:

  1. Enumerate all integer triples (x,y,z) with 1 ≤ x,y,z ≤ 200 that yield positive integer (a,b,c) satisfying the cyclic divisibility conditions, using the derived formulas: a = (xy + x + 1)/(xyz - 1), etc.
  2. Verify each (a,b,c) explicitly and collect all distinct ordered triples T and their sums S=a+b+c.
  3. Build G(d): the number of cyclically divisible triples with sum exactly d.
  4. Precompute v2(n) and v2(n!) for n ≤ N=10^7 using arrays for memory efficiency.
  5. Compute E = Σ_d G(d) * Σ_{k=1}^{⌊N/d⌋} v2((kd)!) using the precomputed v2fact. I will first implement steps 1–3 and inspect the triples and sums; if x,y,z are all comfortably ≤200 I’ll trust completeness, then proceed to steps 4–5. [/THOUGHT] [PYTHON] from math import isclose from collections import defaultdict

Step 1: search for cyclically divisible triples via (x,y,z) up to some bound

def find_triples(max_x): triples = set() xyz_max = 0 for x in range(1, max_x+1): for y in range(1, max_x+1): xy = xy for z in range(1, max_x+1): denom = xyz - 1 if denom <= 0: continue a_num = xy + x + 1 if a_num % denom != 0: continue b_num = yz + y + 1 if b_num % denom != 0: continue c_num = zx + z + 1 if c_num % denom != 0: continue a = a_num // denom b = b_num // denom c = c_num // denom if a <= 0 or b <= 0 or c <= 0: continue # verify the original conditions if (a+1) % b != 0: continue if (b+1) % c != 0: continue if (c+1) % a != 0: continue triples.add((a,b,c)) if xyz > xyz_max: xyz_max = xyz return triples, xyz_max

triples_100, xyz_max_100 = find_triples(100) print("max_x=100: #triples =", len(triples_100), "max xyz =", xyz_max_100) print("Triples (a,b,c):", sorted(triples_100))

Try a larger bound to check if new triples appear

triples_150, xyz_max_150 = find_triples(150) print("max_x=150: #triples =", len(triples_150), "max xyz =", xyz_max_150) new_triples_150 = sorted(triples_150 - triples_100) print("New triples when going 100->150:", new_triples_150)

triples_200, xyz_max_200 = find_triples(200) print("max_x=200: #triples =", len(triples_200), "max xyz =", xyz_max_200) new_triples_200 = sorted(triples_200 - triples_150) print("New triples when going 150->200:", new_triples_200)

Assuming stability by 200, use triples_200

T = sorted(triples_200) print("Final triples T:", T)

Step 2: compute G(d) = count of triples with S=a+b+c = d

G = defaultdict(int) for a,b,c in T: S = a+b+c G[S] += 1

print("G (sum -> count):", dict(sorted(G.items())))

Now compute E using precomputed v2(n) and v2fact(n) for n<=N

from array import array

N = 10_000_000

Precompute v2(n) for n <= N

v2 = array('B', [0]) * (N+1) for n in range(2, N+1): if n & 1: v2[n] = 0 else: v2[n] = v2[n >> 1] + 1

Precompute v2fact(n) for n <= N

v2fact = array('I', [0]) * (N+1) for n in range(1, N+1): v2fact[n] = v2fact[n-1] + v2[n]

Compute E = sum_d G(d) * sum_{k=1}^{floor(N/d)} v2fact[k*d]

E = 0 for d, cnt in G.items(): limit = N // d subtotal = 0 step = d n = d for _ in range(limit): subtotal += v2fact[n] n += step E += cnt * subtotal

print(E)

Tool Output
[PYTHON OUTPUT] max_x=100: #triples = 10 max xyz = 8 Triples (a,b,c): [(1, 1, 1), (1, 1, 2), (1, 2, 1), (1, 2, 3), (2, 1, 1), (2, 3, 1), (3, 1, 2), (3, 4, 5), (4, 5, 3), (5, 3, 4)] max_x=150: #triples = 10 max xyz = 8 New triples when going 100->150: [] max_x=200: #triples = 10 max xyz = 8 New triples when going 150->200: [] Final triples T: [(1, 1, 1), (1, 1, 2), (1, 2, 1), (1, 2, 3), (2, 1, 1), (2, 3, 1), (3, 1, 2), (3, 4, 5), (4, 5, 3), (5, 3, 4)] G (sum -> count): {3: 1, 4: 3, 6: 3, 12: 3} 91666486036450 [/PYTHON OUTPUT]
Reasoning Process

[THOUGHT] Using the classification of all cyclically divisible triples (a,b,c), we determined the multiset of sums S(a,b,c), built the function G from these sums, then used the identity F = G * 1 along with the definition of K and Legendre’s formula for v2(n!) to compute E = v2(K) numerically up to N=10^7. The Python computation yielded E = 91666486036450 with no errors. [/THOUGHT] \boxed{91666486036450}

Final Model Output
91666486036450

Comparative Analysis (P0) (Average across runs)

Avg Time Taken

Deepseek-R1-distill-Qwen-32B (high)
1136.6
Qwen3-30B-A3B-2507
550.5
Solar-Pro-2 (31B)(high)
382.0
Gemini-3-Pro-Preview
302.1
Deepseek-V3.2
287.0
HCX-007(high)
234.6
Grok-4.1-fast
113.6
GPT-5.1 (high)
109.5
Gemma-3-27B
87.5
GPT-oss-20B (high)
79.3
A.X-4.0 (72B)
56.4
Claude-Opus-4.5
39.1
Llama-VARCO-8B-Instruct
31.3
EXAONE-4.0.1-32B (high)
16.2

Avg Token Usage

Solar-Pro-2 (31B)(high)
146942.0
Gemini-3-Pro-Preview
28923.0
Deepseek-R1-distill-Qwen-32B (high)
24609.7
Grok-4.1-fast
20551.3
Deepseek-V3.2
19976.7
Qwen3-30B-A3B-2507
14717.7
GPT-oss-20B (high)
14426.7
GPT-5.1 (high)
11798.0
Claude-Opus-4.5
11332.7
A.X-4.0 (72B)
8872.0
Llama-VARCO-8B-Instruct
5431.3
EXAONE-4.0.1-32B (high)
5162.7
HCX-007(high)
4787.3
Gemma-3-27B
3081.3