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%I #17 Feb 05 2020 04:05:31
%S 1,1,2,1,2,1,3,3,2,1,4,1,2,2,3,1,5,1,4,3,2,1,7,5,2,2,4,1,4,1,6,3,2,2,
%T 5,1,2,2,3,1,6,1,4,4,2,1,9,7,7,3,3,1,4,4,5,3,2,1,8,1,2,2,9,5,5,1,4,3,
%U 3,1,10,1,2,2,4,4,4,1,6,6,2,1,11,5,2,2
%N a(n) is the least positive k such that floor(n/k) is a prime number.
%C This sequence is unbounded; a(n!*p^2) > n where n > 1 and p is a prime number > n.
%H Rémy Sigrist, <a href="/A331954/b331954.txt">Table of n, a(n) for n = 2..10000</a>
%F a(n) = 1 iff n is a prime number.
%e For n = 8:
%e - floor(8/1) = 8 is not a prime number,
%e - floor(8/2) = 4 is not a prime number,
%e - floor(8/3) = 2 is a prime number,
%e - hence a(8) = 3.
%t Array[Block[{k = 1}, While[! PrimeQ@ Floor[#/k], k++]; k] &, 86, 2] (* _Michael De Vlieger_, Feb 04 2020 *)
%o (PARI) a(n) = for (k=1, oo, if (isprime(n\k), return (k)))
%Y Cf. A331953 (square variant), A331959 (corresponding prime numbers).
%K nonn
%O 2,3
%A _Rémy Sigrist_, Feb 02 2020
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