A013812 a(n) = 20^(4*n + 1).

20, 3200000, 512000000000, 81920000000000000, 13107200000000000000000, 2097152000000000000000000000, 335544320000000000000000000000000, 53687091200000000000000000000000000000, 8589934592000000000000000000000000000000000, 1374389534720000000000000000000000000000000000000

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..100
• Tanya Khovanova, Recursive Sequences.
• Index entries for linear recurrences with constant coefficients, signature (160000).

Crossrefs

Subsequence of A009964.

Cf. A013776, A013792, A016813.

Programs

Magma

[20^(4*n+1): n in [0..15]]; // Vincenzo Librandi, Jul 06 2011

Maple

A013812:=n->20^(4*n+1): seq(A013812(n), n=0..10); # Wesley Ivan Hurt, Mar 31 2017

Mathematica

20^(4*Range[0,10]+1) (* or *) NestList[160000#&,20,10] (* Harvey P. Dale, Dec 30 2012 *)

Formula

a(n) = 160000*a(n-1). - Harvey P. Dale, Dec 30 2012

From Elmo R. Oliveira, Jul 13 2025: (Start)

G.f.: 20/(1-160000*x).

E.g.f.: 20*exp(160000*x).

a(n) = A013776(n)*A013792(n) = A009964(A016813(n)). (End)