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 A305781 #5 Jun 10 2018 13:30:26 %S A305781 1,7,37,169,763,3287,14402,60752,261772,1085823,4614736,18868613, %T A305781 79286687,320425251,1333901662,5341972670,22066221462,87764483463, %U A305781 360206083844,1425407602339,5819322422329,22944438320083,93269292846714,366809712490908,1485913213777040 %N A305781 Number of set partitions of [n] with alternating parity of elements and exactly seven blocks. %H A305781 Wikipedia, <a href="https://en.wikipedia.org/wiki/Partition_of_a_set">Partition of a set</a> %Y A305781 Column k=7 of A274581. %K A305781 nonn %O A305781 7,2 %A A305781 _Alois P. Heinz_, Jun 10 2018