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%I #14 Mar 30 2012 19:00:09
%S 1,2,4,3,6,5,10,9,8,16,15,14,13,26,25,24,23,22,21,20,40,39,38,37,36,
%T 35,34,33,32,31,30,60,59,58,57,56,55,54,53,52,51,50,49,48,47,46,92,91,
%U 90,89,88,87,86,85,84,83,82,81,80,79,78,77,76,75,74,73,72,71,70,69
%N Gica-Panaitopol recursion: a(1) = 1; a(n+1) = 2*a(n) if a(n) <= n; otherwise a(n+1) = a(n) - 1.
%C Using the Prime Number Theorem, Gica and Panaitopol show that the sequence contains infinitely many primes.
%D A. Gica and L. Panaitopol, An application of the prime element theorem, Gazeta Matematica 21(100), No. 2 (2003), 113-115.
%H T. D. Noe, <a href="/A193298/b193298.txt">Table of n, a(n) for n = 1..10000</a>
%e The terms occur in disjoint blocks of decreasing consecutive numbers: 1; 2; 4, 3; 6, 5; 10, 9, 8; 16, 15, 14, 13; 26, 25, 24, 23, 22, 21, 20; . . .
%t a[1] = 1; a[n_] := a[n] = If[a[n-1] <= n-1, 2*a[n-1], a[n-1]-1]; Table[a[n], {n, 100}]
%Y Cf. A193299 (sorted sequence), A193300 (subset of primes), A193301 (complement of sorted sequence).
%K nonn
%O 1,2
%A _Jonathan Sondow_, Jul 21 2011
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