OFFSET
1,2
FORMULA
PROG
(PARI) {a(n)=local(M); M=matrix(n+1, n+1, r, c, if(r<c, 0, if(r==0, 1, polcoeff(prod(j=r+1, 2*r, 1-q^j)/prod(j=1, r, 1-q^j), (r+1)*(c-1), q)))); sum(k=0, n, (M^2)[n+1, k+1])}
/* To display results because the offset was changed: */
vector(28, n, a(n-1)) \\ Petros Hadjicostas, May 31 2020
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Mar 12 2007
EXTENSIONS
Offset changed by Petros Hadjicostas, May 31 2020 to agree with A128567
STATUS
approved