A090039 a(1) = 1, otherwise a(n) = floor(e^(n+1)/(e^2 + 1)).

0, 1, 2, 6, 17, 48, 130, 355, 965, 2625, 7137, 19400, 52736, 143353, 389676, 1059250, 2879340, 7826860, 21275611, 57833108, 157206689, 427332086, 1161609045, 3157580759, 8583194400, 23331541370, 63421704936, 172398068058, 468626535665, 1273858996232

Offset

0,3

Comments

a(n+1)/a(n) converges to e.

Links

Table of n, a(n) for n=0..29.

Formula

Let b(0)=0; b(1)=1; b(n+2)=(e-1/e)*b(n+1)+b(n). a(n)=floor(b(n)).

Mathematica

Join[{0, 1}, Table[Floor[E^(n + 1)/(E^2 + 1)], {n, 2, 29}]] (* Arkadiusz Wesolowski, Apr 20 2012 *)

Prog

(PARI) a(n) = if (n==1, 1, exp(n+1)\(exp(2)+1)); \\ Michel Marcus, Jun 21 2017

Crossrefs

Cf. A090426, A090427, A093607, A093608, A182197.

Sequence in context: A200379 A032638 A292229 * A299166 A136776 A018915

Adjacent sequences: A090036 A090037 A090038 * A090040 A090041 A090042

Keyword

nonn

Author

Gary W. Adamson, Nov 20 2003

Extensions

Edited by Don Reble, Nov 14 2005

Name changed by Arkadiusz Wesolowski, Apr 20 2012

Status

approved