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 A055118 #17 Mar 31 2017 22:24:36 %S A055118 0,7,6,5,4,3,2,1,56,63,62,61,60,59,58,57,48,55,54,53,52,51,50,49,40, %T A055118 47,46,45,44,43,42,41,32,39,38,37,36,35,34,33,24,31,30,29,28,27,26,25, %U A055118 16,23,22,21,20,19,18,17,8,15,14,13,12,11,10,9,448,455,454,453,452,451 %N A055118 Base-8 complement of n (write n in base 8, then replace each digit with its base-8 negative). %H A055118 Reinhard Zumkeller, <a href="/A055118/b055118.txt">Table of n, a(n) for n = 0..4095</a> (4095 = 8^4 - 1) %H A055118 <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a> %o A055118 (Haskell) %o A055118 a055118 0 = 0 %o A055118 a055118 n = if d == 0 then 8 * a055118 n' else 8 * a055118 n' + 8 - d %o A055118 where (n', d) = divMod n 8 %o A055118 -- _Reinhard Zumkeller_, Mar 12 2014 %Y A055118 Cf. A004488, A048647, A055115-A055126. %Y A055118 Column k=8 of A248813. %K A055118 base,easy,nonn,look %O A055118 0,2 %A A055118 _Henry Bottomley_, Apr 19 2000