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 A099288 #13 Feb 16 2025 08:32:55 %S A099288 1,6,5,0,4,2,5,7,5,8,7,9,7,5,4,2,8,7,6,0,2,5,3,3,7,7,2,9,5,6,1,3,6,2, %T A099288 4,4,3,8,9,5,6,7,9,8,7,4,8,7,4,0,2,2,8,7,7,6,0,0,2,5,7,9,9,6,3,1,6,1, %U A099288 1,1,3,0,4,9,2,5,6,4,5,9,2,2,5,3,3,8,5,0,1,6,8,5,8,5,4,5,6,1,8,1,4,2,5,3,8 %N A099288 Decimal expansion of the imaginary error function at 1. %H A099288 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Erfi.html">Erfi</a>. %e A099288 1.6504257587975428760253377295613624438956798748740228776002579963... %p A099288 evalf(erfi(1), 120); # _Alois P. Heinz_, Feb 10 2022 %t A099288 RealDigits[ Erfi[1], 10, 105][[1]] %o A099288 (PARI) real(-I*(1.0-erfc(I))) \\ _Michel Marcus_, Oct 07 2020 %o A099288 (PARI) imag(erfc(I)-1) \\ _Charles R Greathouse IV_, Feb 11 2025 %K A099288 cons,nonn %O A099288 1,2 %A A099288 _Robert G. Wilson v_, Oct 11 2004