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 A274489 #18 Nov 15 2018 08:55:23
%S A274489 1,0,1,1,2,5,11,23,50,110,247,565,1308,3067,7264,17355,41790,101327,
%T A274489 247205,606456,1495255,3703422,9210589,22994029,57603919,144770421,
%U A274489 364916488,922357821,2337297441
%N A274489 a(n) = floor(sinh(n) / n^2).
%C A274489 This sequence has some elements in common with A018112 (-> elements 1, 2, 5, 11, 23, 50, 110).
%C A274489 The sum of the reciprocals of a(n) (for n>=2) converges to 2.870623225848376377857...
%F A274489 a(n) = floor(sinh(n)/(n^2)), for n >= 1.
%t A274489 Table[Floor[Sinh[n]/n^2],{n,30}] (* _Harvey P. Dale_, Nov 15 2018 *)
%o A274489 (PARI) a(n)=localprec(19); localprec((n-log(2))\log(10)+9); sinh(n)\n^2 \\ _Charles R Greathouse IV_, Nov 10 2016
%K A274489 nonn,easy,hear
%O A274489 1,5
%A A274489 _Alessandro Polcini_, Nov 10 2016