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 A378424 #27 Dec 06 2024 11:16:31 %S A378424 1,2,3,10,25,78,245,810,2700,9250,32065,112710,400023,1432858,5170575, %T A378424 18784170,68635477,252088416,930138521,3446167850,12815663595, %U A378424 47820447026,178987624513,671825132838,2528212128750,9536895064398,36054433807398,136583761444354,518401146543811,1971076361996550,7506908923471953,28634752211620266 %N A378424 Product_{n>=1} (1+x^n)^a(n) = Sum_{k>=0} C(k)*x^k, where C(k) = A000108(k). %C A378424 Conjecture: A327937(n) divides a(n). %F A378424 Inverse Euler transform of A179277. %o A378424 (PARI) %o A378424 A179277(n) = if(n<=1, 1, sum(k=0,floor(n/2),A179277(k)*binomial(2*n-4*k, n-2*k)/(n-2*k+1))) %o A378424 a(max_n) = {my(va,vb,vc); vc=va=vector(max_n);vb = vector(max_n,k,A179277(k)); for(k=1,max_n,vc[k]=k*vb[k]-sum(m=1,k-1,vc[m]*vb[k-m])); for(k=1,max_n,va[k]=1/k*sumdiv(k,m,moebius(k/m)*vc[m])); va;} %Y A378424 Cf. A000108, A157161, A179277, A327937. %K A378424 nonn %O A378424 1,2 %A A378424 _Thomas Scheuerle_, Nov 26 2024