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 A372339 #15 May 01 2024 02:55:38
%S A372339 1,3,0,3,8,4,8,8,8,7,2,2,0,2,1,2,1,6,5,5,0,7,8,1,4,4,6,5,5,8,9,5,2,7,
%T A372339 8,1,0,4,4,2,0,5,7,3,8,3,4,5,0,5,0,8,8,1,4,3,5,5,7,9,5,1,8,6,1,2,7,1,
%U A372339 2,1,9,9,3,1,0,5,8,9,4,6,3,1,4,5,1,1
%N A372339 Decimal expansion of Sum_{k>=0} (-1)^k * (k+2) / ((k+1)*(2*k)!).
%F A372339 Equals -2 + 3*cos(1) + 2*sin(1).
%e A372339 1.3038488872202121655078144655895278104420573...
%t A372339 s = Sum[(-1)^k (k + 2)/((k + 1) (2 k)!), {k, 0, Infinity}]
%t A372339 d = N[s, 100]
%t A372339 First[RealDigits[d]]
%Y A372339 Cf. A049469, A049470, A372338.
%K A372339 nonn,cons
%O A372339 1,2
%A A372339 _Clark Kimberling_, Apr 28 2024