This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A138315 #2 Mar 30 2012 18:37:10
%S A138315 1,1,1,3,9,45,225,3015,22545,473625,4637025,191508075,2288273625,
%T A138315 123786785925,1735168572225,276775700288175,4433024011291425,
%U A138315 510439906229029425,9196849128341801025,3123191121957643317075
%N A138315 E.g.f. satisfies: A(x) = exp( Sum_{n>=0} a(n)*x^(2n+1)/(2n+1) ).
%e A138315 E.g.f.: A(x) = 1 + x + x^2/2! + 3*x^3/3! + 9*x^4/4! + 45*x^5/5! + 225*x^6/6! +...
%e A138315 Log(A(x)) = x + x^3/3 + x^5/5 + 3*x^7/7 + 9*x^9/9 + 45*x^11/11 + 225*x^13/13 +...
%o A138315 (PARI) {a(n)=local(A=if(n==0,x,sum(k=0,n\2,a(k)*x^(2*k+1)/(2*k+1)))); n!*polcoeff(exp(A+x*O(x^n)),n)}
%Y A138315 Cf. A138314.
%K A138315 nonn
%O A138315 0,4
%A A138315 _Paul D. Hanna_, Mar 13 2008