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 A009405 #36 May 30 2024 03:04:40
%S A009405 0,1,-1,-1,12,-76,480,-3284,24752,-205620,1874340,-18639820,201028080,
%T A009405 -2337859200,29162187600,-388263812000,5492326876800,-82195910554800,
%U A009405 1296105033322800,-21449073720082000,371056401062968000,-6682811910274568000,124750905841882320000
%N A009405 Expansion of e.g.f. log(1+x)*cos(log(1+x)).
%H A009405 Velin Yanev, <a href="/A009405/b009405.txt">Table of n, a(n) for n = 0..450</a>
%F A009405 P-recursive sequence: (n^4 + 2*n^2 + 1)*a(n) + (4*n^3 + 6*n^2 + 8*n + 3)*a(n + 1) + 3*(2*n^2 + 4*n + 3)*a(n + 2) + 2*(2*n + 3)*a(n + 3) + a(n + 4) = 0. - _Velin Yanev_, May 28 2024
%t A009405 Table[n!*SeriesCoefficient[Log[x+1]*Cos[Log[x+1]],{x,0,n}],{n,0,20}] (* _Velin Yanev_, May 21 2024 *)
%t A009405 nmax = 20; CoefficientList[Series[Log[x+1]*Cos[Log[x+1]], {x, 0, nmax}], x] * Range[0, nmax]! (* _Vaclav Kotesovec_, May 29 2024 *)
%t A009405 RecurrenceTable[{(n^4+2*n^2+1)*a[n]+(4*n^3+6*n^2+8*n+3)*a[n+1]+3*(2*n^2+4*n+3)*a[n+2]+2*(2*n+3)*a[n+3]+a[n+4]==0,a[0]==0,a[1]==1,a[2]==-1,a[3]==-1},a,{n,20}] (* _Velin Yanev_, May 29 2024 *)
%K A009405 sign,easy
%O A009405 0,5
%A A009405 _R. H. Hardin_
%E A009405 Extended with signs by _Olivier Gérard_, Mar 15 1997