OFFSET
0,4
FORMULA
a(n) = Sum_{k=0..n} (-1)^(k+1)*A104981(k).
PROG
(PARI) {a(n)=if(n<1, 0, (vector(n+1, k, (-1)^k)*matrix(n+1, n+1, m, j, if(m==j, 1, if(m==j+1, -m+1, -polcoeff((1-1/sum(i=0, m, i!*x^i))/x+O(x^m), m-j-1))))^-1)[2])}
CROSSREFS
KEYWORD
sign
AUTHOR
Paul D. Hanna, Mar 09 2006
STATUS
approved