A115283 Diagonal sums of correlation triangle for 3-2*0^n.

1, 3, 6, 13, 18, 27, 37, 48, 60, 76, 90, 108, 127, 147, 168, 193, 216, 243, 271, 300, 330, 364, 396, 432, 469, 507, 546, 589, 630, 675, 721, 768, 816, 868, 918, 972, 1027, 1083, 1140, 1201, 1260, 1323, 1387, 1452, 1518, 1588, 1656, 1728, 1801

Offset

0,2

Comments

Diagonal sums of number triangle A115282.

Links

Table of n, a(n) for n=0..48.

Index entries for linear recurrences with constant coefficients, signature (1,1,0,-1,-1,1).

Formula

G.f.: (1+2x)(1+2x^2)/((1-x)(1-x^2)(1-x^3)); a(n)=sum{k=0..floor(n/2), sum{j=0..n-k, [j<=k]*(3-2*0^(k-j))*[j<=n-2k]*(3-2*0^(n-2k-j))}}.

Crossrefs

Sequence in context: A053569 A310123 A293794 * A078382 A075651 A091277

Adjacent sequences: A115280 A115281 A115282 * A115284 A115285 A115286

Keyword

easy,nonn

Author

Paul Barry, Jan 19 2006

Status

approved