A064777 Numbers k such that prime(k) - pi(k) is divisible by k.
1, 2, 3, 18, 42, 95, 524, 273585, 1735537, 4406057, 4406063, 4406188, 4406196, 4406341, 4406539, 4406541, 28703894, 73694240, 73694281, 73694287, 73694360, 73694363, 73694410, 3287860772, 3287860773, 3287860880, 3287860889, 3287860895, 3287860897
Offset: 1
Keywords
Examples
k = 18 is a term: prime(18) = 61, pi(18) = 7, and (61-7)/18 = 54/18 = 3.
Programs
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Mathematica
Do[ If[ IntegerQ[ (Prime[n] - PrimePi[n])/n ], Print[n]], {n, 1, 6*10^7} ] Select[Range[5000000],Divisible[Prime[#]-PrimePi[#],#]&] (* Harvey P. Dale, Aug 12 2013 *) -
PARI
isok(k) = ((prime(k) - primepi(k)) % k) == 0; \\ Michel Marcus, Jun 15 2021
Extensions
a(18)-a(23) from Donovan Johnson, Apr 23 2010
a(24)-a(29) from Donovan Johnson, Oct 17 2012