A237990 Numbers m such that the numbers of primes, even positive integers and odd positive integers less than or equal to m are all even.

4, 8, 16, 20, 40, 44, 56, 64, 72, 80, 92, 96, 108, 116, 120, 124, 132, 136, 140, 144, 148, 152, 156, 164, 176, 184, 188, 196, 200, 204, 208, 224, 232, 240, 252, 256, 264, 268, 272

Offset: 1

Author

Ivan N. Ianakiev, Feb 16 2014

Keywords

• nonn
• easy

Comments

A subsequence of A008586.

Examples

			A tetrahedral die whose faces are marked with the numbers from 1 to 4 has an even number of sides marked with prime numbers, even integers and odd integers. Therefore, 4 is in the sequence.
		

Links

• Ivan N. Ianakiev, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A008586, A237989.

Programs

Mathematica

Select[Range[4, 1000, 4], EvenQ[PrimePi[#]] &] (* Paolo Xausa, Jun 24 2024 *)

Formula

a(n) == 0 (mod 4)