A013768 a(n) = 21^(3*n + 1).

21, 194481, 1801088541, 16679880978201, 154472377739119461, 1430568690241985328321, 13248496640331026125580781, 122694327386105632949003612841, 1136272165922724266740722458520501, 10523016528610349434285830688358359761

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 (9261).

Mathematica

21^(3*Range[0, 10]+1) (* or *) NestList[9261#&, 21, 10] (* Harvey P. Dale, Apr 30 2020 *)

Prog

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

Crossrefs

Subsequence of A009965.

Sequence in context: A189310 A068735 A172800 * A182149 A358665 A203673

Adjacent sequences: A013765 A013766 A013767 * A013769 A013770 A013771

Keyword

nonn,easy

Author

N. J. A. Sloane

Status

approved