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 A071824 Number of x with largest prime factor of the form 4k+1 less than or equal to n. 0

%I

%S 0,0,0,1,1,1,1,1,2,2,2,3,3,4,4,5,5,5,6,6,6,6,6,7,8,8,8,9,10,10,10,10,

%T 11,11,11,12,12,13,14,15,15,15,15,16,16,16,16,16,17,18,19,20,20,20,20,

%U 20,21,21,22,23,23,23,23,24,24,24,25,25,25,25,25,26,27,28,28,28,29,29

%N Number of x with largest prime factor of the form 4k+1 less than or equal to n.

%C Conjecture : for n > 1000 a(n) - n/2 < - sqrt(n) ( if b(n) denotes the number of x with largest prime factor of the form 4k+3 less than or equal to n, it is conjectured that if n > 1000 b(n)- n/2 > sqrt(n) )

%o (PARI) for(n=2,200,print1(sum(i=2,n,if((component(component(factor(i),1),omega(i))-1)%4,0,1)),","))

%K easy,nonn

%O 1,9

%A _Benoit Cloitre_, Jun 07 2002

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Last modified March 24 14:39 EDT 2023. Contains 361479 sequences. (Running on oeis4.)