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A261213 Odd numbers n such that n^2 = m + (m+1), where both m and m+1 have no repeated digits. 1

%I #15 Feb 26 2018 03:07:28

%S 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 109,113,121,125,127,129,137,163,193,219,239,271,273,279,281,285,305,

%U 311,315,331,339,353,357,377,381,395,403,409,435,441,443,597

%N Odd numbers n such that n^2 = m + (m+1), where both m and m+1 have no repeated digits.

%C 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 Pieter Post, <a href="/A261213/b261213.txt">Table of n, a(n) for n = 1..146</a>

%e 5 is in the sequence, because 5^2 = 25. 25 = 12 + 13. 12 and 13 both have no repeating digits.

%t 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 Cf. A036745, A071519, A156977.

%K nonn,full,fini,base

%O 1,2

%A _Pieter Post_, Aug 12 2015

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Last modified March 28 10:31 EDT 2024. Contains 371240 sequences. (Running on oeis4.)