A188476 Diagonal sums of number triangle A188474.

1, 1, 2, 6, 12, 27, 65, 150, 353, 843, 2014, 4843, 11713, 28433, 69292, 169470, 415754, 1022868, 2523120, 6238645, 15459561, 38387191, 95497612, 237989801, 594062697, 1485141397, 3718116380, 9320941698, 23396109986, 58795356627, 147920737819

Offset

0,3

Comments

Hankel transform is A188477(n+1).

Links

Table of n, a(n) for n=0..30.

Formula

a(n)=sum{k=0..floor(n/2), sum{j=0..n-2k+1, (j/(n-k+2-j))*C(n-k+2-j,n-k+1)*C(n-k+2-j,k+1)*2^(j-1)}}.

Conjecture: (n+3)*a(n) +(-4*n-9)*a(n-1) +n*a(n-2) -3*a(n-3) +3*(5*n+1)*a

(n-4) +6*(n)*a(n-5) +6*(n-1)*a(n-6) +4*(-n+3)*a(n-7)=0. - R. J. Mathar, Dec 03 2014

Crossrefs

Sequence in context: A335712 A356465 A166963 * A155583 A140853 A185961

Adjacent sequences: A188473 A188474 A188475 * A188477 A188478 A188479

Keyword

nonn,easy

Author

Paul Barry, Apr 01 2011

Status

approved