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 A280882 #4 Jan 12 2017 15:04:31 %S A280882 1,10,20,245,56,2100,2640,36795,8140,542542,72436,3311945,6050240, %T A280882 91668080,2505120,1972220235,92327460,5331136090,6360277000, %U A280882 320219686633,29187262016,4567704520100,3125812500200,39433339579725,19033980625296,2173716576665550 %N A280882 Number of set partitions of [n] into exactly four blocks where sizes of distinct blocks are coprime. %H A280882 Wikipedia, <a href="https://en.wikipedia.org/wiki/Coprime_integers">Coprime integers</a> %H A280882 Wikipedia, <a href="https://en.wikipedia.org/wiki/Partition_of_a_set">Partition of a set</a> %Y A280882 Column k=4 of A280880. %K A280882 nonn %O A280882 4,2 %A A280882 _Alois P. Heinz_, Jan 09 2017