Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.
%I #7 Jun 14 2016 18:04:03
%S 1,1,4,21,131,921,7083,58493,512342,4718671,45407919,454384447,
%T 4710818128,50453504549,556929098189,6324139809301,73759635547026,
%U 882440215196461,10817350790774790,135741743078330321,1742225569514045719,22854838454769204603,306233932315912508708,4188667660550945874199,58453992283916684321847,831867972069915069340899
%N G.f. A(x) satisfies: A(x - x/(1-x)*A(x)) = x.
%F G.f. A(x) satisfies:
%F (1) A(x) = x + Sum_{n>=1} (d/dx)^(n-1) ( x/(1-x)*A(x) )^n / n!.
%F (2) A(x) = x * exp( Sum_{n>=1} (d/dx)^(n-1) (1/x) * ( x/(1-x)*A(x) )^n / n! ).
%e G.f.: A(x) = x + x^2 + 4*x^3 + 21*x^4 + 131*x^5 + 921*x^6 + 7083*x^7 + 58493*x^8 + 512342*x^9 + 4718671*x^10 + 45407919*x^11 + 454384447*x^12 +...
%o (PARI) {a(n) = my(A=x); for(i=1,n, A = serreverse(x - x/(1-x)*A +x*O(x^n)) ); polcoeff(A,n)}
%o for(n=1,30,print1(a(n),", "))
%K nonn
%O 1,3
%A _Paul D. Hanna_, Jun 10 2016