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 A048221 #8 Jun 06 2021 02:52:38 %S A048221 2,5,18,35,60,94,134,180,232,291,357,430,515,610,710,815,932,1053, %T A048221 1181,1318,1462,1615,1776,1944,2116,2300,2496,2696,2907,3128,3351, %U A048221 3581,3817,4062,4318,4582,4852,5131,5419,5719,6031,6346,6665,6991,7323,7665,8015 %N A048221 a(n)=T(2n-1,n), array T given by A048212. %F A048221 a(n) = A004979(2*n) - A004979(n). - _Sean A. Irvine_, Jun 05 2021 %Y A048221 Cf. A004979. %K A048221 nonn %O A048221 1,1 %A A048221 _Clark Kimberling_ %E A048221 More terms from _Sean A. Irvine_, Jun 05 2021