A013897 a(n) = 20^(5*n + 4).

160000, 512000000000, 1638400000000000000, 5242880000000000000000000, 16777216000000000000000000000000, 53687091200000000000000000000000000000, 171798691840000000000000000000000000000000000, 549755813888000000000000000000000000000000000000000

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..50
• Tanya Khovanova, Recursive Sequences.
• Index entries for linear recurrences with constant coefficients, signature (3200000).

Crossrefs

Subsequence of A009964.

Cf. A013825, A013857, A016897.

Programs

Magma

[20^(5*n+4): n in [0..10]]; // Vincenzo Librandi, May 27 2011

Mathematica

20^(5*Range[0,10]+4) (* or *) NestList[3200000#&,160000,10] (* Harvey P. Dale, Feb 15 2016 *)

Formula

a(n) = 3200000*a(n-1), a(0)=160000. - Vincenzo Librandi, May 27 2011

From Elmo R. Oliveira, Jul 11 2025: (Start)

G.f.: 160000/(1-3200000*x).

E.g.f.: 160000*exp(3200000*x).

a(n) = A013825(n)*A013857(n) = A009964(A016897(n)). (End)