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 A138871 #14 Feb 16 2024 11:24:26 %S A138871 2,4,16,64,96,536,144,824,976,56,64,864,576,64,544,504,176,536,496, %T A138871 304,56,776,96,736,376,256,336,104,504,656,224,944,296,264,856,576, %U A138871 136,896,536,24,704,624,936,936,464,376,256,976 %N A138871 Last 3 digits of n-th even superperfect number A061652(n). %C A138871 Also, last 3 digits of n-th superperfect number A019279(n), if there are no odd superperfect numbers. %F A138871 a(n) = 2^(A000043(n)-1) mod 1000. - _Max Alekseyev_, Feb 16 2024 %Y A138871 Cf. A019279, A061652, A138865, A138867, A138870, A138872. %K A138871 nonn,base,more %O A138871 1,1 %A A138871 _Omar E. Pol_, Apr 02 2008 %E A138871 More terms from _R. J. Mathar_, Feb 05 2010 %E A138871 a(40)-a(41) from _Max Alekseyev_, Feb 11 2012 %E A138871 a(42)-a(47) from _Jinyuan Wang_, Mar 14 2020 %E A138871 a(48) from _Max Alekseyev_, Feb 16 2024