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%I #12 Jun 17 2017 03:04:37
%S 1,3,6,8,10,13,12,4,5,11,14,2,7,9,15,16,17,18,19,20,21,22,23,24,25,26,
%T 27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,
%U 50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72
%N a(n) = smallest number m, not occurring earlier, such that a(k)+m is a square for some k<n; a(1) = 1.
%C Permutation of the natural numbers with inverse A099136;
%C a(n) <> n iff 1 < n <= 14.
%H <a href="/index/Per#IntegerPermutation">Index entries for sequences that are permutations of the natural numbers</a>
%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1).
%o (PARI) a(n)=if(n>14,n,[1, 3, 6, 8, 10, 13, 12, 4, 5, 11, 14, 2, 7, 9][n]) \\ _Charles R Greathouse IV_, Sep 02 2011
%Y Cf. A048761, A068527.
%K nonn,easy
%O 1,2
%A _Reinhard Zumkeller_, Sep 29 2004
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