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 A108529 #30 Aug 31 2018 15:57:15 %S A108529 1,1,2,5,16,51,177,621,2246,8245,30783,116257,443945,1710255,6640939, %T A108529 25961690,102105115,403701135,1603721999,6397931901,25621989760, %U A108529 102965680728,415091909292,1678226164646,6803121058354,27645628327636 %N A108529 Number of asymmetric mobiles (cycle rooted trees) with n generators. %C A108529 A generator is a leaf or a node with just one child. %C A108529 Here CHK(A(x)) = 1 - Sum_{n>=1} (mu(n)/n)*log(1-A(x^n)), i.e., the constant 1 is included in the definition of the CHK transform. For other sequences that involve the CHK transform, the 1 is sometimes dropped; e.g., see sequence A032171. We have CHK(A(x)) = x + x^2 + 3*x^3 + 8*x^4 + 27*x^5 + 86*x^6 + 303*x^7 + 1065*x^8 + 3871*x^9 + ... - _Petros Hadjicostas_, Dec 05 2017 %H A108529 Andrew Howroyd, <a href="/A108529/b108529.txt">Table of n, a(n) for n = 1..200</a> %H A108529 C. G. Bower, <a href="/transforms2.html">Transforms (2)</a> %H A108529 <a href="/index/Mo#mobiles">Index entries for sequences related to mobiles</a> %F A108529 G.f. satisfies: (2-x)*A(x) = x - 1 + CHK(A(x)). %F A108529 From _Petros Hadjicostas_, Dec 05 2017: (Start) %F A108529 a(n) = (1/2)*(a(n-1) + (1/n)*Sum_{d|n} mu(d)*c(n/d)) for n>=2, where c(n) = n*a(n) + Sum_{s=1..n-1} c(s)*a(n-s) and a(1) = c(1) = 1. %F A108529 The g.f. satisfies (2-x)*A(x) = x - Sum_{n>=1} (mu(n)/n)*log(1-A(x^n)). (This is just a rephrasing of C. Bower's equation above.) %F A108529 The auxiliary sequence (c(n): n>=1} has g.f. C(x) = Sum_{n>=1} c(n)*x^n = x*(dA/dx)/(1-A(x)) = x + 3*x^2 + 10*x^3 + 35*x^4 + 136*x^5 + 528*x^6 + 2122*x^7 + ... %F A108529 (End) %o A108529 (PARI) %o A108529 CHK(p,n)={sum(d=1, n, moebius(d)/d*log(subst(1/(1+O(x*x^(n\d))-p), x, x^d)))} %o A108529 seq(n)={my(p=x); for(n=2, n, p += x^n*polcoef(x*p + CHK(p, n), n)); Vecrev(p/x)} \\ _Andrew Howroyd_, Aug 31 2018 %Y A108529 Cf. A108521, A108522, A108523, A108524, A108525, A108527, A108528, A032171. %K A108529 nonn %O A108529 1,3 %A A108529 _Christian G. Bower_, Jun 07 2005