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 A055115 #13 Mar 31 2017 22:26:35 %S A055115 0,4,3,2,1,20,24,23,22,21,15,19,18,17,16,10,14,13,12,11,5,9,8,7,6,100, %T A055115 104,103,102,101,120,124,123,122,121,115,119,118,117,116,110,114,113, %U A055115 112,111,105,109,108,107,106,75,79,78,77,76,95,99,98,97,96,90,94,93,92 %N A055115 Base-5 complement of n (write n in base 5, then replace each digit with its base-5 negative). %H A055115 Alois P. Heinz, <a href="/A055115/b055115.txt">Table of n, a(n) for n = 0..3124</a> %H A055115 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %Y A055115 Cf. A004488, A048647, A055115-A055126. %Y A055115 Column k=5 of A248813. %K A055115 base,easy,nonn %O A055115 0,2 %A A055115 _Henry Bottomley_, Apr 19 2000