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 A026412 #8 Sep 27 2019 02:50:55 %S A026412 1,4,9,18,27,40,55,72,89,113,140,167,194,221,253,294,329,369,419,452, %T A026412 502,552,618,677,721,776,836,894,976,1049,1121,1175,1248,1348,1415, %U A026412 1489,1574,1658,1756,1845,1925,2037,2122,2224,2356,2442,2551,2635,2762,2875,3000 %N A026412 a(n) = position of the n-th n in A026409. %K A026412 nonn %O A026412 1,2 %A A026412 _Clark Kimberling_ %E A026412 More terms from _Sean A. Irvine_, Sep 26 2019