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 A377542 #13 Mar 30 2025 20:23:48
%S A377542 1,0,9,4,2,1,9,8,0,7,6,1,3,2,3,8,3,1,9,4,1,8,3,8,4,9,7,0,3,5,2,2,3,2,
%T A377542 2,7,1,6,2,9,6,8,6,3,6,1,4,1,2,7,8,3,3,6,1,0,5,9,6,4,3,1,0,5,2,8,9,7,
%U A377542 2,5,9,6,9,2,2,2,9,6,6,4,7,3,8,8,5,5,1,6,5,7,4,8,3,8,7,8,0,4,3,1
%N A377542 Decimal expansion of Gamma(1/4)^4/(16*Pi^2).
%D A377542 Steven R. Finch, Mathematical Constants, Encyclopedia of Mathematics and its Applications, vol. 94, Cambridge University Press, 2003, Section 1.5.4, p. 34.
%H A377542 Michael I. Shamos, <a href="http://euro.ecom.cmu.edu/people/faculty/mshamos/cat.pdf">A catalog of the real numbers</a>, (2007). See p. 134.
%H A377542 <a href="/index/Ga#gamma_function">Index to sequences related to the Gamma function</a>.
%H A377542 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a>.
%F A377542 Equals Product_{n>=1} (1 - 1/(2*n + 1)^2)^(-1)^n (see Finch).
%F A377542 Equals Product_{n>=1} (4*n - 1)^2*((4*n + 1)^2 - 1)/(((4*n - 1)^2 - 1)*(4*n + 1)^2) (see Shamos).
%F A377542 Equals 2*(Gamma(5/4)/Gamma(3/4))^2.
%F A377542 Equals A254794/2. - _Hugo Pfoertner_, Oct 31 2024
%e A377542 1.09421980761323831941838497035223227162968636141...
%t A377542 RealDigits[Gamma[1/4]^4/(16Pi^2),10,100][[1]]
%Y A377542 Cf. A002388, A068465, A068466, A068467, A254794.
%K A377542 nonn,cons,easy
%O A377542 1,3
%A A377542 _Stefano Spezia_, Oct 31 2024