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 A253169 #15 Mar 26 2015 13:59:35 %S A253169 1,2,9,5,6,36,10,11,12,100,17,18,19,20,225,26,27,28,29,30,441,37,38, %T A253169 39,40,41,42,784,50,51,52,53,54,55,56,1296,65,66,67,68,69,70,71,72, %U A253169 2025,82,83,84,85,86,87,88,89,90,3025,101,102,103,104,105,106,107 %N A253169 Smallest m such that A256188(m) = n. %C A253169 A256188(a(n)) = n and A256188(m) != n for m < a(n). %H A253169 Reinhard Zumkeller, <a href="/A253169/b253169.txt">Table of n, a(n) for n = 1..10000</a> %F A253169 a(n) = if n triangular then n^2 else A004202(n + 1 - A002024(n)). %o A253169 (Haskell) %o A253169 import Data.List (elemIndex); import Data.Maybe (fromJust) %o A253169 a253169 = (+ 1) . fromJust . (`elemIndex` a256188_list) %Y A253169 Cf. A256188, A000537, A010054, A000290. %K A253169 nonn %O A253169 1,2 %A A253169 _Reinhard Zumkeller_, Mar 26 2015