A013767 a(n) = 20^(3*n + 2).

400, 3200000, 25600000000, 204800000000000, 1638400000000000000, 13107200000000000000000, 104857600000000000000000000, 838860800000000000000000000000, 6710886400000000000000000000000000, 53687091200000000000000000000000000000, 429496729600000000000000000000000000000000

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..200
• Tanya Khovanova, Recursive Sequences.
• Index entries for linear recurrences with constant coefficients, signature (8000).

Crossrefs

Subsequence of A009964.

Cf. A013731, A013747, A016789.

Programs

Magma

[20^(3*n+2): n in [0..10]]; // Vincenzo Librandi, Jun 27 2011

Mathematica

NestList[8000#&,400,10] (* Harvey P. Dale, May 11 2018 *)

PARI

a(n)=20^(3*n+2) \\ Charles R Greathouse IV, Jul 10 2016

Formula

From Elmo R. Oliveira, Feb 27 2025: (Start)

G.f.: 400/(1 - 8000*x).

E.g.f.: 400*exp(8000*x).

a(n) = A013731(n)*A013747(n) = A009964(A016789(n)). (End)