A191636 - OEIS

%I #21 Sep 08 2022 08:45:57

%S 3,5,12,36,113,372,1260,4369,15420,55188,199728,729444,2684354,

%T 9942053,37025580,138547332,520602096,1963413621,7429132620,

%U 28192605840,107269427100,409120605684,1563749870614,5988829291716,22977549119237,88305875046480,339894311499660

%N a(n) = floor((-1 + 4^n)/(-1 + 2*n)).

%H Vincenzo Librandi, <a href="/A191636/b191636.txt">Table of n, a(n) for n = 1..1000</a>

%t f[n_] := Floor[(-1+4^n)/(-1+2 n)]

%t Table[f[n], {n, 1, 40}]     (* A191636 *)

%o (Magma) [Floor((-1+4^n)/(-1+2*n)): n in [1..30] ];// _Vincenzo Librandi_, Sep 10 2011

%o (Maxima) A191636(n):=floor((-1+4^n)/(-1+2*n))$ makelist(A191636(n),n,1,30); /* _Martin Ettl_, Oct 25 2012 */

%Y Cf. A191637.

%K nonn

%O 1,1

%A _Clark Kimberling_, Jun 09 2011