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 A143051 Smallest number not occurring earlier and smaller than the largest square so far, the next square if no such number exists. 5

%I

%S 0,1,4,2,3,9,5,6,7,8,16,10,11,12,13,14,15,25,17,18,19,20,21,22,23,24,

%T 36,26,27,28,29,30,31,32,33,34,35,49,37,38,39,40,41,42,43,44,45,46,47,

%U 48,64,50,51,52,53,54,55,56,57,58,59,60,61,62,63,81,65,66,67,68,69,70,71

%N Smallest number not occurring earlier and smaller than the largest square so far, the next square if no such number exists.

%C Permutation of the natural numbers, inverse: A143052;

%C A143053(n) = a(a(n));

%C a(A000290(n)) = A005563(n-1);

%C a(A002522(n)) = A000290(n+1);

%C for n>1: GCD(a(n^2),a(n^2+1)) = A050873(A000290(n),A002522(n)) =

%C A022998(n+1).

%H Peter Kagey, <a href="/A143051/b143051.txt">Table of n, a(n) for n = 0..10000</a>

%H <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a>

%F a(n) = if n=0 then 0 else if n=1+k^2 then n+2*k else n-1.

%K nonn

%O 0,3

%A _Reinhard Zumkeller_, Jul 20 2008

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Last modified May 18 09:26 EDT 2021. Contains 343995 sequences. (Running on oeis4.)