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 A255487 #14 Oct 19 2017 10:46:18 %S A255487 1,1,1,2,7,27,164,1316,12757,134174,1474341,16588434 %N A255487 Number of polyhypercubes or 4-dimensional polyominoes with n cells (regarding mirror-images as distinct). %D A255487 _Don Reble_, Personal communication, Feb 25 2015 %F A255487 a(n) = A006760(n) + A006765(n) + A006766(n) + signum(n-1) for n >= 1. - _Sean A. Irvine_, Jul 19 2017 %Y A255487 Cf. A049429, A049430, A068870. %K A255487 hard,nonn %O A255487 0,4 %A A255487 _N. J. A. Sloane_, Mar 01 2015