A191637 a(n) = floor((1 + 4^n)/(1 + 2*n)).

1, 3, 9, 28, 93, 315, 1092, 3855, 13797, 49932, 182361, 671088, 2485513, 9256395, 34636833, 130150524, 490853405, 1857283155, 7048151460, 26817356775, 102280151421, 390937467653, 1497207322929, 5744387279809, 22076468761620, 84973577874915, 327534518354217

Offset: 1

Author

Clark Kimberling, Jun 09 2011

Keywords

• nonn

Links

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

Crossrefs

Cf. A191636.

Programs

Magma

[Floor((1+4^n)/(1+2*n)): n in [1..30] ]; // Vincenzo Librandi, Sep 10 2011

Mathematica

f[n_] := Floor[(1+4^n)/(1+2 n)]
Table[f[n], {n, 1, 40}]     (* A191637 *)

Maxima

A191637(n):=floor((1+4^n)/(1+2*n))$ makelist(A191637(n),n,1,30); /* Martin Ettl, Oct 25 2012 */