A138477 Mix A084175 and 2*A084175.

0, 0, 1, 2, 3, 6, 15, 30, 55, 110, 231, 462, 903, 1806, 3655, 7310, 14535, 29070, 58311, 116622, 232903, 465806, 932295, 1864590, 3727815, 7455630, 14913991, 29827982, 59650503

Offset

0,4

Links

Table of n, a(n) for n=0..28.

Formula

O.g.f.: x^2/((2*x-1)(x-1)(1+x)(1+2*x^2)). a(2n) = A084175(n). a(2n+1)=2*A084175(n). a(n) = 2a(n-1) -a(n-2) +2a(n-3) +2a(n-4) -4a(n-5). - R. J. Mathar, May 19 2008

Crossrefs

Sequence in context: A346776 A371570 A100249 * A182240 A352901 A052102

Adjacent sequences: A138474 A138475 A138476 * A138478 A138479 A138480

Keyword

nonn

Author

Paul Curtz, May 18 2008

Extensions

More terms from R. J. Mathar, May 19 2008

Status

approved