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%I #14 Aug 17 2015 15:38:47
%S 1,5,6,2,23,8,27,9,3,10,34,11,37,12,39,4,42,43,14,45,46,15,48,49,16,
%T 51,52,17,54,55,56,18,58,59,188,19,61,62,63,20,203,65,66,21,213,68,69,
%U 22,7,71,72,229,73,74,235,75,24,241,77,78,247,25,251,80,81,257,26,83,263,84,267,85,86,273,87,276,88,28,89
%N a(n) is the smallest number not already in the sequence such that a(n)^2 begins with n.
%C Conjectured to be a permutation of the natural numbers.
%C Differs from A018851 at n = 25.
%H Derek Orr, <a href="/A260463/b260463.txt">Table of n, a(n) for n = 1..10000</a>
%F a(n) >= sqrt(n) for all n > 0. If a(n) = sqrt(n), then n is a square. Note the converse is false: a(25) = 16.
%o (PARI) v=[];k=1;while(#v<100,d=digits(k^2);D=digits(#v+1);if(#D<=#d,c=1;for(i=1,#D,if(D[i]!=d[i],c=0;break));if(c&&!vecsearch(vecsort(v),k),v=concat(v,k);k=0));k++);v
%Y Cf. A018851.
%K nonn,base
%O 1,2
%A _Derek Orr_, Jul 26 2015
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