OFFSET
1,2
EXAMPLE
L.g.f.: A(x) = x + 3x^2/2 + 4x^3/3 + 7x^4/4 + 11x^5/5 + 12x^6/6 + 15x^7/7 +...
exp(A(x)) = 1 + x + 2x^2 + 3x^3 + 5x^4 + 8x^5 + 12x^6 + 18x^7 +...(A132842).
PROG
(PARI) {a(n)=local(A, t, r=1); A=if(n==1, [1], vector(n-1, j, a(j)/j)); if(n==1, r=1, for(j=1, n, if(denominator(Vec(exp(x*Ser(concat(A, (a(n-1)+j)/n))))[n+1])==1, r=a(n-1)+j; j=n+1))); r}
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Sep 12 2007
STATUS
approved