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 A274861 #3 Jul 09 2016 17:35:27 %S A274861 1,1,2,4,8,16,32,64,128,264,544,1120,2304,4940,10632,22908,49324, %T A274861 112352,258184,596430,1379150,3431265,8639020,21965049,56062850, %U A274861 155582125,436328469,1238168841,3534962983,10951026755,34135076965,107562008116,341226376721 %N A274861 Number of set partitions of [n] such that the difference between each element and its index (in the partition) is a multiple of four. %Y A274861 Column k=4 of A274859. %K A274861 nonn %O A274861 0,3 %A A274861 _Alois P. Heinz_, Jul 09 2016