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 A261879 #16 Feb 16 2025 08:33:27
%S A261879 2,1,2,7,3,9,9,5,9,2,3,9,8,5,2,6,5,5,2,7,2,3,5,4,3,9,3,3,7,5,9,3,2,0,
%T A261879 3,7,2,9,1,7,5,2,2,7,2,9,1,5,6,9,1,8,3,3,2,5,5,1,8,4,4,5,0,4,9,7,0,2,
%U A261879 4,4,2,6,1,4,0,7,3,0,8,6,9,8,8,9,3,3,2,2,6,5,6,6,9,7,1,4,9,7,7,7,4,4,0,7,8
%N A261879 Decimal expansion of BesselI(3,2).
%H A261879 G. C. Greubel, <a href="/A261879/b261879.txt">Table of n, a(n) for n = 0..2500</a>
%H A261879 Eric Weisstein's MathWorld, <a href="https://mathworld.wolfram.com/ModifiedBesselFunctionoftheFirstKind.html">Modified Bessel Function of the First Kind</a>
%F A261879 Sum_{k>=1} 1/((k - 2)!*(k + 1)!).
%F A261879 Also S(2) - S(1), using _Peter Bala_'s notation in A229020.
%e A261879 0.212739959239852655272354393375932037291752272915691833255184450497...
%t A261879 RealDigits[BesselI[3, 2], 10, 105][[1]]
%o A261879 (PARI) besseli(3,2) \\ _Altug Alkan_, Nov 19 2015
%Y A261879 Cf. A070910 (BesselI(0,2)), A096789 (BesselI(1,2)), A229020 (BesselI(2,2)).
%K A261879 nonn,cons,easy
%O A261879 0,1
%A A261879 _Jean-François Alcover_, Nov 19 2015