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

1,2

Links

Table of n, a(n) for n=1..29.

Example

k = 18 is a term: prime(18) = 61, pi(18) = 7, and (61-7)/18 = 54/18 = 3.

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 *)

Prog

(PARI) isok(k) = ((prime(k) - primepi(k)) % k) == 0; \\ Michel Marcus, Jun 15 2021

Crossrefs

Cf. A000040, A000720, A065139, A111181.

Sequence in context: A073529 A134850 A163910 * A137784 A053195 A347429

Adjacent sequences: A064774 A064775 A064776 * A064778 A064779 A064780

Keyword

nonn

Author

Labos Elemer and Robert G. Wilson v, Oct 18 2001

Extensions

a(18)-a(23) from Donovan Johnson, Apr 23 2010

a(24)-a(29) from Donovan Johnson, Oct 17 2012

Status

approved