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 A229939 #18 Jun 18 2024 03:29:16
%S A229939 2,8,2,7,4,3,3,3,8,8,2,3,0,8,1,3,9,1,4,6,1,6,3,7,9,0,4,4,9,5,1,5,5,2,
%T A229939 5,9,5,7,7,7,4,5,2,4,5,9,4,3,7,5,9,5,2,3,8,8,7,7,4,5,0,1,3,3,0,7,7,0,
%U A229939 3,4,7,6,5,6,5,7,5,8,8,0,9,8,7,6,5,2,3,1,3,4,2,8,0,7,9,0,5,3,6,1,1,8,3,9
%N A229939 Decimal expansion of 9*Pi/10.
%C A229939 With offset 2, decimal expansion of 9*Pi.
%C A229939 9*Pi is also the surface area of a sphere whose diameter equals the square root of 9. More generally x*Pi is also the surface area of a sphere whose diameter equals the square root of x. - _Omar E. Pol_, Dec 22 2013
%H A229939 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a>
%F A229939 9*Pi = Sum_{j >= 0} j*(j - 1)*(j - 2)*(j - 3)*2^(j+1) / ((2*j + 1)*binomial(2*j, j)). - _Peter Bala_, Nov 21 2023
%e A229939 9*Pi/10 = 2.827433388230813914616379044951552595777...
%e A229939 9*Pi = 28.27433388230813914616379044951552595777...
%t A229939 First[RealDigits[9*Pi, 10, 100]] (* _Paolo Xausa_, Jun 18 2024 *)
%o A229939 (PARI) .9*Pi \\ _Charles R Greathouse IV_, Oct 01 2022
%Y A229939 Cf. A000796, A019692, A122952, A019694, A019669, A228719, A228721, A228824 (Pi through 8*Pi).
%K A229939 nonn,cons
%O A229939 1,1
%A A229939 _Omar E. Pol_, Oct 06 2013