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 A059580 #6 Sep 29 2022 15:23:02 %S A059580 1,4,52,912,17992,377004,8189036,182127464,4118242896,94264009684, %T A059580 2177854717348,50687305553024,1186694487776152,27918432252733692, %U A059580 659490547066121820,15632281755808999768,371637556504994957728,8857868330404952584100,211598146901545394669844 %N A059580 Main diagonal of the array A059579. %K A059580 easy,nonn %O A059580 1,2 %A A059580 _Floor van Lamoen_, Jan 23 2001 %E A059580 More terms from _Sean A. Irvine_, Sep 29 2022