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 A122938 #3 Mar 30 2012 18:36:59
%S A122938 1,1,1,2,6,27,160,1189,10600,110161,1306629,17408293,257299241,
%T A122938 4177017722,73872560359,1413560616317,29096001945172,641010535303531,
%U A122938 15049350893772391,375084409475304164,9890697492431533299
%N A122938 G.f. A(x) satisfies: A(x+x^2) = A(x)^2/(1+x).
%C A122938 Self-convolution equals A122939. See A122888 for the table of self-compositions of x+x^2.
%F A122938 G.f.: A(x) = Product_{n>=0} (1 + F_n(x) )^(1/2^(n+1)) where F_0(x)=x, F_{n+1}(x)=F_n(x+x^2); a product that involves the n-th self-compositions of x+x^2.
%e A122938 G.f.: A(x) = (1 + x)^(1/2) * (1 + x+x^2)^(1/4) * (1 + x+2x^2+2x^3+x^4)^(1/8) * (1 + x+3x^2+6x^3+9x^4+10x^5+8x^6+4x^7+x^8)^(1/16) *...
%o A122938 (PARI) {a(n)=local(A=1+x+x*O(x^n)); for(i=0,n,A=-A+2*sqrt((1+x)*subst(A,x,x+x^2+x*O(x^n))));polcoeff(A,n)}
%Y A122938 Cf. A122939 (A^2), A122940 (log), A122941-A122945; A122888 (table).
%K A122938 nonn
%O A122938 0,4
%A A122938 _Paul D. Hanna_, Sep 21 2006