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 A257173 #4 Apr 17 2015 16:04:25 %S A257173 0,1,2,3,69,5,9,7,40,171,365,11,805,13,217,49,637,17,1519,19,671,125, %T A257173 403,23,143,2891,1199,1351,917,29,559,31,799,1099,323,14443,949,37, %U A257173 803,5027,679,41,2167,43,1837,6253,341,47,253,2327,169,4697,2021,53 %N A257173 Smallest number m such that A248737(m) = n. %C A257173 A248737(a(n)) = n and A248737(m) != n for m < a(n). %H A257173 Reinhard Zumkeller, <a href="/A257173/b257173.txt">Table of n, a(n) for n = 0..90</a> %o A257173 (Haskell) %o A257173 import Data.List (elemIndex); import Data.Maybe (fromJust) %o A257173 a257173 = fromJust . (`elemIndex` a248737_list) %Y A257173 Cf. A248737. %K A257173 nonn %O A257173 0,3 %A A257173 _Reinhard Zumkeller_, Apr 17 2015