A100236 Main diagonal of triangle A100235.

1, 4, 26, 139, 726, 3774, 19601, 101784, 528526, 2744419, 14250626, 73997554, 384238401, 1995189564, 10360186226, 53796120699, 279340789726, 1450500069334, 7531841136401, 39109705751344, 203080369893126

Offset

0,2

Links

Table of n, a(n) for n=0..20.

Formula

a(n) = 5*a(n-1) + a(n-2) + 5 for n>1, with a(0)=1, a(1)=4. G.f.: Sum_{n>=1} a(n)*x^n/n = log((1-x)/(1-5*x-x^2)).

Prog

(PARI) a(n)=if(n==0, 1, n*polcoeff(log((1-x)/(1-5*x-x^2)+x*O(x^n)), n))

Crossrefs

Cf. A100233, A100235.

Equals A087130(n) - 1.

Sequence in context: A359962 A316539 A197964 * A229278 A180226 A325587

Adjacent sequences: A100233 A100234 A100235 * A100237 A100238 A100239

Keyword

nonn

Author

Paul D. Hanna, Nov 30 2004

Status

approved