A368369 AGM transform of odd numbers.

0, 4, 324, 38656, 6812500, 1691793216, 566933589544, 247467140448256, 136744348012840296, 93452709250000000000, 77479910616937022101996, 76677271817228569527975936, 89338843947334074736463717884, 121104748419604219251183463776256, 189040371972603446582336425781250000, 336742459165125951045187297509382291456

Offset: 1

Author

N. J. A. Sloane, Jan 24 2024

Keywords

• nonn

Comments

See A368366 for further information.

Links

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

Crossrefs

Cf. A005408, A368366.

Programs

Mathematica

A368369[n_] := With[{m = n^n}, m*(m-(2*n-1)!!)];
Array[A368369, 20] (* Paolo Xausa, Jan 29 2024 *)

PARI

a368369(n) = {my(v=vector(n, i, i+i-1)); vecsum(v)^n - n^n*vecprod(v)}; \\ Hugo Pfoertner, Jan 24 2024

Python

from sympy import factorial2
def A368369(n): return (m:=n**n)*(m-factorial2((n<<1)-1)) # Chai Wah Wu, Jan 25 2024