A025255 a(n) = a(1)*a(n-1) + a(2)*a(n-2) + ...+ a(n-3)*a(3) for n >= 4.

1, 3, 1, 1, 4, 8, 22, 55, 145, 386, 1039, 2837, 7808, 21693, 60697, 170959, 484306, 1379020, 3944780, 11330962, 32668988, 94510169, 274262571, 798153211, 2328830794, 6811354123, 19966156857, 58647721275, 172600025350, 508870577560, 1502795261440

Offset

1,2

Links

Table of n, a(n) for n=1..31.

Formula

Conjecture: n*a(n) +(-2*n+3)*a(n-1) +5*(-n+3)*a(n-2) +(2*n-9)*a(n-3) +9*(n-6)*a(n-4)=0. - R. J. Mathar, Feb 25 2015

Crossrefs

Sequence in context: A160870 A345279 A342447 * A296006 A245397 A346792

Adjacent sequences: A025252 A025253 A025254 * A025256 A025257 A025258

Keyword

nonn

Author

Clark Kimberling

Status

approved