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 A084248 #23 Sep 02 2025 21:58:22
%S A084248 5,0,7,9,2,2,0,2,0,8,6,6,3,6,7,8,3,3,6,0,4,3,6,8,7,9,5,6,7,8,2,0,2,1,
%T A084248 0,7,4,8,3,2,3,9,7,3,4,5,7,0,8,3,5,9,7,7,4,2,8,4,8,2,4,3,7,9,1,6,8,7,
%U A084248 4,5,9,0,9,3,2,9,1,9,9,0,6,9,4,7,0,1,5,4,5,4,9,0,2,3,3,4,9,0,3,6,1,0,2,8,8
%N A084248 Decimal expansion of c = Product_{k>=1} (1 + 1/t(k)) where t(k) = k(k+1)/2 is the k-th triangular number.
%D A084248 Bruce C. Berndt, Ramanujan Notebook part II, Infinite series, Springer Verlag, 1989, p. 241.
%H A084248 Kelvin Voskuijl, <a href="/A084248/b084248.txt">Table of n, a(n) for n = 1..20000</a>
%F A084248 Equals ((1/2)/Pi)*cosh(Pi/2*sqrt(7)).
%e A084248 5.07922020866367833604368795...
%t A084248 RealDigits[Cosh[Pi/2*Sqrt[7]]/(2*Pi), 10, 120][[1]] (* _Amiram Eldar_, Jun 01 2023 *)
%o A084248 (PARI) 1/2/Pi*cosh(Pi/2*sqrt(7))
%Y A084248 Cf. A000217.
%K A084248 cons,nonn,changed
%O A084248 1,1
%A A084248 _Benoit Cloitre_, Jun 21 2003