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 A371499 #9 Jul 01 2024 05:10:12
%S A371499 2,0,4,1,6,6,9,4,2,2,3,9,8,6,3,6,8,6,0,0,2,9,0,5,5,8,6,0,7,2,1,0,6,6,
%T A371499 2,9,1,1,7,5,3,7,9,7,4,8,0,0,7,6,6,3,5,1,3,3,1,5,4,8,9,1,4,5,6,7,4,8,
%U A371499 4,6,8,0,2,0,0,4,7,6,1,8,9,8,3,9,9,4
%N A371499 Decimal expansion of Sum_{k>=0} 1/(k^2)!.
%F A371499 (This constant) - (constant in A371498) = 2.00000551146384...
%e A371499 2.04166942239863686002905586072...
%t A371499 s[x_] := s[x] = Sum[x^n/((n^2)!), {n, 0, Infinity}]
%t A371499 First[RealDigits[N[s[1], 100]]]
%o A371499 (PARI) suminf(k=0,1/(k^2)!) \\ _Hugo Pfoertner_, Mar 30 2024
%Y A371499 Cf. A255322, A371498.
%K A371499 nonn,cons
%O A371499 0,1
%A A371499 _Clark Kimberling_, Mar 30 2024