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 A261213 #15 Feb 26 2018 03:07:28 %S A261213 1,3,5,7,9,11,13,23,27,29,31,35,37,39,41,43,57,63,69,77,81,87,89,95, %T A261213 109,113,121,125,127,129,137,163,193,219,239,271,273,279,281,285,305, %U A261213 311,315,331,339,353,357,377,381,395,403,409,435,441,443,597 %N A261213 Odd numbers n such that n^2 = m + (m+1), where both m and m+1 have no repeated digits. %C A261213 This sequence is finite and a(146) = 40797 is the last term. 40797^2 = 1664395209 and 1664395209 = 832197604 + 832197605. These last two numbers both have no repeating digits. %H A261213 Pieter Post, <a href="/A261213/b261213.txt">Table of n, a(n) for n = 1..146</a> %e A261213 5 is in the sequence, because 5^2 = 25. 25 = 12 + 13. 12 and 13 both have no repeating digits. %t A261213 nr[n_] := 1 == Max@ DigitCount@ n; Select[ Range[1, 10^5, 2], nr[x= Floor[#^2 / 2]] && nr[x + 1] &] (* _Giovanni Resta_, Aug 12 2015 *) %Y A261213 Cf. A036745, A071519, A156977. %K A261213 nonn,full,fini,base %O A261213 1,2 %A A261213 _Pieter Post_, Aug 12 2015