A128083 Sum of squared coefficients of q in the q-analog of the odd double factorials.

1, 1, 3, 37, 1159, 66953, 6158021, 825889193, 152147002939, 36866098462221, 11368538145120143, 4347671960639941039, 2019396728684584627337, 1119792551093682455434255, 730724550040451849614251167

Offset

0,3

Links

Table of n, a(n) for n=0..14.

Prog

(PARI) {a(n)=if(n==0, 1, sum(k=0, n^2, polcoeff(prod(j=1, n, (1-q^(2*j-1))/(1-q)), k, q)^2))}

Crossrefs

Cf. A001147 ((2n-1)!!); A128080 (triangle), A128081 (central terms), A128082 (diagonal); A127728, A128087.

Sequence in context: A354334 A051396 A113074 * A270751 A270584 A175771

Adjacent sequences: A128080 A128081 A128082 * A128084 A128085 A128086

Keyword

nonn

Author

Paul D. Hanna, Feb 14 2007

Status

approved