A191638 a(n) = floor((-1 + 4^n)/(-1 + 3*n)).

1, 3, 7, 23, 73, 240, 819, 2849, 10082, 36157, 131071, 479349, 1766022, 6547206, 24403223, 91382282, 343597383, 1296593900, 4908534052, 18635790301, 70936234050, 270649016067, 1034834473200, 3964436291699, 15214863605981, 58488306848967, 225179981368524

Offset

1,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Mathematica

f[n_] := Floor[(-1+4^n)/(-1+3 n)]
Table[f[n], {n, 1, 40}]     (* A191638 *)

Prog

(Magma) [Floor((-1+4^n)/(-1+3*n)): n in [1..30] ]; // Vincenzo Librandi, Sep 10 2011
(Maxima) A191638(n):=floor((-1+4^n)/(-1+3*n))$ makelist(A191638(n), n, 1, 30); /* Martin Ettl, Oct 25 2012 */

Crossrefs

Cf. A191639.

Sequence in context: A133435 A079061 A228724 * A148704 A283109 A339284

Adjacent sequences: A191635 A191636 A191637 * A191639 A191640 A191641

Keyword

nonn

Author

Clark Kimberling, Jun 09 2011

Status

approved