OFFSET
0,4
COMMENTS
PROG
(PARI) {a(n)=local(M); M=matrix(n+1, n+1, m, j, if(m>=j, binomial(m-1-(j-1)\2, j\2)*binomial(m-1-j\2, (j-1)\2))); return((M^-1)[n+1, 1])}
CROSSREFS
KEYWORD
sign
AUTHOR
Paul D. Hanna, Mar 16 2005
STATUS
approved