0,2

E.g.f.: exp(x)/(1 - x - x^2/2!) = 1 + 2*x + 6*x^2/2! + 25*x^3/3! + 137*x^4/4! + 936*x^5/5! + 7672*x^6/6! +... + a(n)*x^n/n! +...

where a(n) = 1 + n*a(n-1) + n*(n-1)*a(n-2)/2.

(PARI) a(n)=n!*polcoeff(exp(x+x*O(x^n))/(1-x-x^2/2! +x*O(x^n)), n)

Cf. A087214, A000629, A128231, A128232.

Sequence in context: A020010 A102812 A020100 this_sequence A084784 A135881 A007815

Adjacent sequences: A128227 A128228 A128229 this_sequence A128231 A128232 A128233

nonn

Paul D. Hanna (pauldhanna(AT)juno.com), Feb 20 2007