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 A371745 #20 May 03 2024 15:19:39
%S A371745 2,2,3,2,4,4,2,7,5,4,8,3,9,3,2,7,3,0,7,0,5,9,4,1,2,5,0,7,0,3,5,7,4,6,
%T A371745 0,2,9,7,7,4,3,6,5,4,2,2,1,4,6,6,4,3,5,9,0,1,5,6,0,0,6,7,5,3,6,4,9,2,
%U A371745 1,2,0,3,5,5,6,9,5,1,1,0,2,4,1,5,2,3
%N A371745 Decimal expansion of Sum_{k>=0} (-1)^k * k / ((k+1) (2k)!).
%F A371745 Equals 2 - cos(1) - 2 sin(1).
%e A371745 -0.2232442754839327307059412507035746029774...
%t A371745 s = Sum[(-1)^k k/((k + 1) (2 k)!), {k, 0, Infinity}]
%t A371745 d = N[s, 100]
%t A371745 First[RealDigits[d]]
%Y A371745 Cf. A372339, A372340.
%K A371745 nonn,cons
%O A371745 0,1
%A A371745 _Clark Kimberling_, May 01 2024