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 A230286 #12 Mar 04 2017 06:27:01 %S A230286 1,2,4,5,7,8,10,11,13,17,19,23,28,32,37,38,40,41,43,47,49,53,58,62,67, %T A230286 68,70,71,73,77,79,83,88,92,97,101,103,107,109,113,118,122,127,131, %U A230286 136,140,142,146,151,155,160,164 %N A230286 a(n) = A016052(n)/3. %C A230286 a(1) = 1; for n >= 1, a(n+1) = a(n) + sum of its digits. %H A230286 Reinhard Zumkeller, <a href="/A230286/b230286.txt">Table of n, a(n) for n = 1..10000</a> %H A230286 <a href="/index/Coi#Colombian">Index entries for Colombian or self numbers and related sequences</a> %o A230286 (Haskell) %o A230286 a230286 = (flip div 3) . a016052 %Y A230286 Cf. A004207, A016052, A230287 (first differences). %K A230286 nonn,base %O A230286 1,2 %A A230286 _Reinhard Zumkeller_ and _N. J. A. Sloane_, Oct 16 2013