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 A305780 #5 Jun 10 2018 13:30:09 %S A305780 1,6,27,108,409,1558,5692,21328,76468,282885,999383,3656887,12772925, %T A305780 46306978,160408850,577077226,1987559778,7105490315,24379316121, %U A305780 86719101209,296819500851,1051663900480,3594472289644,12696988924724,43364647235536,152825304753761 %N A305780 Number of set partitions of [n] with alternating parity of elements and exactly six blocks. %H A305780 Wikipedia, <a href="https://en.wikipedia.org/wiki/Partition_of_a_set">Partition of a set</a> %Y A305780 Column k=6 of A274581. %K A305780 nonn %O A305780 6,2 %A A305780 _Alois P. Heinz_, Jun 10 2018