A027167 a(n) = Sum_{k=0..floor(n/2)} A027157(n-k, k).

1, 2, 4, 7, 15, 24, 50, 81, 165, 266, 544, 875, 1787, 2876, 5870, 9445, 19281, 31022, 63324, 101887, 207975, 334624, 683050, 1099001, 2243325, 3609426, 7367704, 11854355, 24197587, 38932996, 79471590, 127866765, 261006761

Offset

0,2

Links

Table of n, a(n) for n=0..32.

Formula

Empirical g.f.: (1+x)^2*(1-x+x^2) / ((1-x)*(1-2*x^2-3*x^4-4*x^6)). - Colin Barker, Feb 20 2016

Crossrefs

Sequence in context: A002956 A333613 A171276 * A259090 A358832 A232464

Adjacent sequences: A027164 A027165 A027166 * A027168 A027169 A027170

Keyword

nonn

Author

Clark Kimberling

Status

approved