A013766 a(n) = 20^(3*n + 1).

20, 160000, 1280000000, 10240000000000, 81920000000000000, 655360000000000000000, 5242880000000000000000000, 41943040000000000000000000000, 335544320000000000000000000000000, 2684354560000000000000000000000000000, 21474836480000000000000000000000000000000

Offset

0,1

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).

Formula

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

G.f.: 20/(1 - 8000*x).

E.g.f.: 20*exp(8000*x).

a(n) = A013730(n)*A013746(n) = A009964(A016777(n)). (End)

Mathematica

20^(3Range[0, 10]+1) (* Harvey P. Dale, Jun 23 2011 *)

Prog

(Magma) [20^(3*n+1): n in [0..10]]; // Vincenzo Librandi, Jun 27 2011
(Maxima) makelist(20^(3*n+1), n, 0, 20); /* Martin Ettl, Oct 21 2012 */
(PARI) a(n)=20^(3*n+1) \\ Charles R Greathouse IV, Jul 10 2016

Crossrefs

Subsequence of A009964.

Cf. A013730, A013746, A016777.

Sequence in context: A222745 A175853 A340167 * A078354 A203306 A211489

Adjacent sequences: A013763 A013764 A013765 * A013767 A013768 A013769

Keyword

nonn,easy,changed

Author

N. J. A. Sloane

Status

approved