A317796 Denominator of the coefficient of z^(-n) in the Stirling-like asymptotic expansion of Product_{z=1..n} z^(z^2).

1, 360, 259200, 1959552000, 2821754880000, 5079158784000000, 76796880814080000000, 304115648023756800000000, 125121866615488512000000000, 258236518070374430146560000000000, 929651465053347948527616000000000000, 334674527419205261469941760000000000000, 920050700832433373350094438400000000000000

Offset: 0

Author

Seiichi Manyama, Sep 01 2018

Keywords

• nonn
• frac

Comments

1^(1^2)*2^(2^2)*...*n^(n^2) ~ A_2*n^(n^3/3+n^2/2+n/6)*exp(-n^3/9+n/12)*(Sum_{k>=0} b(k)/n^k)^n, where A_2 is the second Bendersky constant.

a(n) is the denominator of b(n).

Examples

			1^(1^2)*2^(2^2)*...*n^(n^2) ~ A_2*n^(n^3/3+n^2/2+n/6)*exp(-n^3/9+n/12)*(1 - 1/(360*n) + 1/(259200*n^2) + 259193/(1959552000*n^3) - 1036793/(2821754880000*n^4) - 201551328007/(5079158784000000*n^5) + ... ).
		

Links

• Seiichi Manyama, Table of n, a(n) for n = 0..206
• Weiping Wang, Some asymptotic expansions on hyperfactorial functions and generalized Glaisher-Kinkelin constants, ResearchGate, 2017.

Crossrefs

Product_{z=1..n} z^(z^m): A001163/A001164 (m=0), A143475/A143476 (m=1), A317747/A317796 (m=2).

Cf. A051675, A243262 (A_2).

Formula

Let B_n be the Bernoulli number, and define the sequence {c_n} by the recurrence

c_0 = 1, c_n = (2/n) * Sum_{k=0..n-1} B_{n-k+3}*c_k/((n-j+1)*(n-k+2)*(n-k+3)) for n > 0.

a(n) is the denominator of c_n.