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 A194044 #13 Mar 11 2015 01:35:24 %S A194044 1,4,38,472,6685,102340,1649446,27574712,473750970,8313682000, %T A194044 148383186924,2685209034144,49154880453275,908609423877476, %U A194044 16935710715505290,317951375873760120,6006975695929624776,114120962913881862036,2178813296304338702764 %N A194044 G.f. satisfies: A(x) = ( Sum_{n>=0} q^(n*(n+1)/2) )^4 where q=x*A(x)^2. %F A194044 The g.f. A(x) satisfies: %F A194044 (1) A(x) = Sum_{n>=0} (2*n+1)*x^n*A(x)^(2*n)/(1 - x^(2*n+1)*A(x)^(4*n+2)), %F A194044 (2) A(x)^2 = Sum_{n>=0} (n+1)^3*x^n*A(x)^(2*n)/(1 - x^(2*n+2)*A(x)^(4*n+4)), %F A194044 (3) A(x) = Product_{n>=1} (1 + x^n*A(x)^(2*n))^4*(1 - x^(2*n)*A(x)^(4*n))^4, %F A194044 (4) A(x) = exp( Sum_{n>=1} 4*(x^n*A(x)^(2*n)/(1 + x^n*A(x)^(2*n)))/n ), %F A194044 (5) A(x/F(x)^8) = F(x)^4 where F(x) = Sum_{n>=0} x^(n*(n+1)/2), %F A194044 due to q-series identities. %F A194044 Self-convolution 2nd power equals A194042. %F A194044 Self-convolution 4th root equals A194043. %e A194044 G.f.: A(x) = 1 + 4*x + 38*x^2 + 472*x^3 + 6685*x^4 + 102340*x^5 +... %e A194044 where %e A194044 (0) A(x)^(1/4) = 1 + x*A(x)^2 + x^3*A(x)^6 + x^6*A(x)^12 + x^10*A(x)^20 + x^15*A(x)^30 + x^21*A(x)^42 +... +... %e A194044 (1) A(x) = 1/(1-x*A(x)^2) + 3*x*A(x)^2/(1-x^3*A(x)^6) + 5*x^2*A(x)^4/(1-x^5*A(x)^10) + 7*x^3*A(x)^6/(1-x^7*A(x)^14) +... %e A194044 (2) A(x)^2 = 1/(1-x^2*A(x)^4) + 8*x*A(x)^2/(1-x^4*A(x)^8) + 27*x^2*A(x)^4/(1-x^6*A(x)^12) + 64*x^3*A(x)^6/(1-x^8*A(x)^16) +... %e A194044 (3) A(x) = (1+x*A(x)^2)^4*(1-x^2*A(x)^4)^4 * (1+x^2*A(x)^4)^4*(1-x^4*A(x)^8)^4 * (1+x^3*A(x)^6)^4*(1-x^6*A(x)^12)^4 * (1+x^4*A(x)^8)^4*(1-x^8*A(x)^16)^4 *... %e A194044 (4) log(A(x)) = 4*x*A(x)^2/(1+x*A(x)^2) + 4*(x^2*A(x)^4/(1+x^2*A(x)^4))/2 + 4*(x^3*A(x)^6/(1+x^3*A(x)^6))/3 + 4*(x^4*A(x)^8/(1+x^4*A(x)^8))/4 +... %e A194044 Related expansions begin: %e A194044 _ A(x)^(1/4) = 1 + x + 8*x^2 + 93*x^3 + 1272*x^4 + 19058*x^5 + 302705*x^6 + 5007234*x^7 + 85341048*x^8 +...+ A194043(n)*x^n +... %e A194044 _ A(x)^2 = 1 + 8*x + 92*x^2 + 1248*x^3 + 18590*x^4 + 294032*x^5 + 4848456*x^6 + 82433472*x^7 + 1434755717*x^8 +...+ A194042(n)*x^n +... %o A194044 (PARI) {a(n)=local(A=1+x, T=sum(m=0, sqrtint(2*n+1), x^(m*(m+1)/2))+x*O(x^n)); A=(serreverse(x/T^8)/x)^(1/2); polcoeff(A, n)} %o A194044 (PARI) {a(n)=local(A=1+x);for(i=1,n,A=sum(m=0,n,(x*A^2+x*O(x^n))^(m*(m+1)/2))^4);polcoeff(A,n)} %o A194044 (PARI) {a(n)=local(A=1+x);for(i=1,n,A=sum(m=0,n,(2*m+1)*(x*A^2)^m/(1-(x*A^2+x*O(x^n))^(2*m+1))));polcoeff(A,n)} %o A194044 (PARI) {a(n)=local(A=1+x);for(i=1,n,A=sum(m=0,n,(m+1)^3*(x*A^2)^m/(1-(x*A^2+x*O(x^n))^(2*m+2)))^(1/2));polcoeff(A,n)} %o A194044 (PARI) {a(n)=local(A=1+x);for(i=1,n,A=prod(m=1,n,(1+(x*A^2)^m)*(1-(x*A^2)^(2*m)+x*O(x^n)))^4); polcoeff(A, n)} %o A194044 (PARI) {a(n)=local(A=1+x);for(i=1,n,A=exp(sum(m=1,n,4*(x*A^2)^m/(1+(x*A^2)^m+x*O(x^n))/m))); polcoeff(A, n)} %Y A194044 Cf. A194042, A194043. %K A194044 nonn %O A194044 0,2 %A A194044 _Paul D. Hanna_, Aug 12 2011