A369395 AGM transform of the even positive numbers.

0, 4, 432, 61696, 12300000, 3339123264, 1195810789376, 549031054934016, 315439869711260160, 222215334010000000000, 188664842745174745939968, 190234762349632291168321536, 224946256003775354246877765632, 308520390288000443379128425267200, 486093585063330330624000000000000000

Offset: 1

Author

Hugo Pfoertner, Jan 24 2024

Keywords

• nonn
• easy

Comments

See A368366 for the definition of the AGM transform.

Links

• Paolo Xausa, Table of n, a(n) for n = 1..210

Crossrefs

Cf. A299174, A368366, A368367-A368371, A369394.

Programs

Mathematica

A369395[n_] := n^n*((n+1)^n - (2*n)!!);
Array[A369395, 15] (* Paolo Xausa, Jan 29 2024 *)

PARI

a369395(n) = {my(v=vector(n,i,i+i)); vecsum(v)^n - n^n*vecprod(v)};

Python

from math import factorial
def A369395(n): return n**n*((n+1)**n-(factorial(n)<Chai Wah Wu, Jan 25 2024