OFFSET
0,3
FORMULA
a(n) = sum(k=1..n, (a(k-1)/(k-1)!*sum((-1)^i * (k-2*i)^n * binomial(k,i), i,0,k))/2^k), a(0)=1.
PROG
(Maxima)
a(n):=if n=0 then 1 else sum((a(k-1)/(k-1)!*sum((-1)^i*(k-2*i)^n*binomial(k, i), i, 0, k))/2^k, k, 1, n);
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Kruchinin, Nov 28 2011
STATUS
approved