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 A334383 #25 Dec 21 2024 01:02:19
%S A334383 5,5,9,1,3,4,1,4,4,4,1,8,9,7,9,9,1,7,4,8,8,2,6,8,4,6,7,9,1,6,8,9,6,4,
%T A334383 0,9,8,0,6,3,6,2,5,0,4,0,3,0,9,8,3,8,6,5,7,1,5,3,1,1,7,3,4,2,1,9,7,1,
%U A334383 7,1,2,9,2,2,8,0,2,3,1,2,6,5,1,5,7,1,0,4,4,1,9,0,2,3,4,7,2,9,4,9,4,0,8,7,4,4,9,4,4,8
%N A334383 Decimal expansion of Sum_{k>=0} (-1)^k/(2^k*(k!)^2).
%H A334383 <a href="/index/Be#Bessel">Index entries for sequences related to Bessel functions or polynomials</a>
%H A334383 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a>
%F A334383 Equals BesselJ(0,sqrt(2)).
%F A334383 Equals BesselI(0,sqrt(2)*i), where BesselI is the modified Bessel function of order 0. - _Jianing Song_, Sep 18 2021
%e A334383 1/(2^0*0!^2) - 1/(2^1*1!^2) + 1/(2^2*2!^2) - 1/(2^3*3!^2) + ... = 0.5591341444189799174882684679...
%t A334383 RealDigits[BesselJ[0, Sqrt[2]], 10, 110] [[1]]
%o A334383 (PARI) besselj(0, sqrt(2)) \\ _Michel Marcus_, Apr 26 2020
%Y A334383 Cf. A055546, A092605.
%Y A334383 Bessel function values: A334380 (J(0,1)), this sequence (J(0,sqrt(2))), A091681 (J(0,2)), A197036 (I(0,1)), A334381 (I(0,sqrt(2))), A070910 (I(0,2)).
%K A334383 nonn,cons
%O A334383 0,1
%A A334383 _Ilya Gutkovskiy_, Apr 25 2020