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A070295 Smallest composite number such that there are exactly n primes less than it (and coprime to it) which do not divide it, or 0 if no such number exists. 0

%I #3 Dec 05 2013 19:55:19

%S 4,10,8,14,16,20,24,25,33,32,0,44,48,49,66,62,64,72,74,80,81,91,98,

%T 105,104,108,111,115,121,128,140,141,154,152,158,164,171,169,182,183,

%U 192,194,204,200,212,224,230,232,235,246,242,243,256,265,273,272,278,285

%N Smallest composite number such that there are exactly n primes less than it (and coprime to it) which do not divide it, or 0 if no such number exists.

%C Are there any zero values other than a(11) = 0?

%e a(4) = 14: primes up to 14 are 2, 3, 5, 7, 11, 13 out of which four primes 3, 5, 11 and 13 are coprime to 14.

%K nonn

%O 1,1

%A _Amarnath Murthy_, May 10 2002

%E Corrected and extended by Larry Reeves (larryr(AT)acm.org), Oct 01 2002

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Last modified May 21 05:34 EDT 2024. Contains 372728 sequences. (Running on oeis4.)