OFFSET
0,2
COMMENTS
FORMULA
a(n) = sum_{k=0..n} sum_{i=0..k} (n-k)^(k-i)*binomial(k, i)*(i+1)!
O.g.f.: Sum_{m>=0, n>=1} n!*x^(m+n-1)/(1-m*x)^n - Vladeta Jovovic, Nov 18 2003
PROG
(PARI) a(n)=if(n<0, 0, sum(k=0, n, sum(i=0, k, (n-k)^(k-i)*binomial(k, i)*(i+1)!)))
(PARI) a(n)=sum(k=0, n, sum(i=0, k, (n-k)^(k-i)*binomial(k, i)*(i+1)!));
(PARI) a(n)=polcoeff(sum(m=0, 2*n, sum(k=1, 2*n, k!*x^(m+k-1)/(1-m*x)^k), x*O(x^n)), n);
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Nov 14 2003
STATUS
approved