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 A348333 #10 Oct 15 2021 09:40:46
%S A348333 3,0,8,3,3,3,8,8,4,4,7,9,7,2,7,3,7,2,0,0,5,8,1,1,1,7,2,1,4,4,2,1,3,2,
%T A348333 5,8,2,3,5,0,7,5,9,4,9,6,0,1,5,3,2,7,0,2,6,6,3,0,9,7,8,2,9,1,3,4,9,6,
%U A348333 9,3,6,0,4,0,0,9,5,2,3,7,9,6,7,9,8,9,5,0,4,2
%N A348333 Decimal expansion of Sum_{n=-oo..oo} 1/(n^2)!.
%C A348333 This constant is irrational. The proof is similar to the one that e is irrational. Is this constant transcendental?
%e A348333 3.083338844797273...
%t A348333 RealDigits[N[1 + 2 *Sum[1/(n^2)!, {n, 1, Infinity}], 90]][[1]] (* _Amiram Eldar_, Oct 14 2021 *)
%o A348333 (PARI) 1 + 2*suminf(n=1, 1/(n^2)!)
%Y A348333 Cf. A195907, A001113 (e = Sum_{n>=0} 1/n!).
%K A348333 nonn,cons
%O A348333 1,1
%A A348333 _Jianing Song_, Oct 13 2021