A013778 a(n) = 3^(4*n + 1).

3, 243, 19683, 1594323, 129140163, 10460353203, 847288609443, 68630377364883, 5559060566555523, 450283905890997363, 36472996377170786403, 2954312706550833698643, 239299329230617529590083, 19383245667680019896796723

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• easy

Comments

Equivalently, powers of 3 with final digit 3. - Muniru A Asiru, Feb 06 2019

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 (81).

Programs

GAP

List([0..15],n->3^(4*n+1)); # Muniru A Asiru, Feb 06 2019

Magma

[3^(4*n+1): n in [0..20]]; // Vincenzo Librandi, Jun 27 2011

Maple

seq(coeff(series(3/(1-81*x),x,n+1), x, n), n = 0 .. 15); # Muniru A Asiru, Feb 06 2019

Mathematica

3^(1 + 4Range[0, 15]) (* Harvey P. Dale, Jan 31 2011 *)
NestList[81#&,3,20] (* Harvey P. Dale, Feb 26 2023 *)

Maxima

makelist(3^(4*n+1),n,0,20); /* Martin Ettl, Oct 21 2012 */

Formula

From Philippe Deléham, Nov 25 2008: (Start)

a(n) = 81*a(n-1); a(0)=3.

G.f.: 3/(1-81*x). (End)