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 A134200 #25 Nov 18 2024 22:32:20 %S A134200 0,1,2,9,68,725,9942,166453,3290632,75017097,1937420010,55906879809, %T A134200 1782695466444,62247810769053,2362246665531326,96806321000599725, %U A134200 4260677055123222544,200440759819510706321,10037364633737549049042,533071599267242747118585 %N A134200 E.g.f. satisfies: A(x) = x*(exp(sinh(A(x)))). %H A134200 Alois P. Heinz, <a href="/A134200/b134200.txt">Table of n, a(n) for n = 0..300</a> %F A134200 a(n) = sum(k=1..n-1, ((sum(i=0..k, (-1)^i*(k-2*i)^(n-1)* C(k,i))) *n^k)/(2^k*k!)), a(0)=0, a(1)=1. - _Vladimir Kruchinin_, May 10 2011 %F A134200 a(n) ~ n^(n-1) / (exp(n) * r^n * sqrt(1/s^2+sinh(s))), where r = 0.3296546568511367672... and s = 0.7650099545507321226... are roots of the system of equations exp(sinh(s))*r = s, s*cosh(s) = 1. - _Vaclav Kotesovec_, Jul 16 2014 %p A134200 A:= proc(n) option remember; if n=0 then 0 else convert (series (x* (exp (sinh(A(n-1)))), x=0, n+1), polynom) fi end: a:= n-> coeff (A(n), x, n)*n!: seq (a(n), n=0..30); %t A134200 CoefficientList[InverseSeries[Series[x/E^Sinh[x],{x,0,20}],x],x] * Range[0,20]! (* _Vaclav Kotesovec_, Jul 16 2014 *) %o A134200 (Maxima) a(n):=if n<2 then n else sum(((sum((-1)^i*(k-2*i)^(n-1) *binomial(k,i), i,0,k))*n^k)/(2^k*k!),k,1,n-1); /* _Vladimir Kruchinin_, May 10 2011 */ %K A134200 nonn %O A134200 0,3 %A A134200 _Alois P. Heinz_, Aug 27 2008