OFFSET
0,3
FORMULA
a(n) = [prod_{j=0..n-1} (1-4*j)]/n! * 4^(n*(n-1)/2).
PROG
(PARI) {a(n)=local(m=1, p=4, q=4, r=1); prod(j=0, n-1, m*r-p*j)/n!*q^(n*(n-1)/2)}
CROSSREFS
KEYWORD
sign
AUTHOR
Paul D. Hanna, Mar 14 2006
STATUS
approved