A210998 Composite numbers that are in the gap between an even-indexed prime and an odd-indexed prime.

4, 8, 9, 10, 14, 15, 16, 20, 21, 22, 30, 38, 39, 40, 44, 45, 46, 54, 55, 56, 57, 58, 62, 63, 64, 65, 66, 72, 80, 81, 82, 90, 91, 92, 93, 94, 95, 96, 102, 108, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 132, 133, 134, 135, 136

Offset: 1

Author

Omar E. Pol, Sep 26 2012

Keywords

• nonn
• easy

Examples

			Illustration of initial terms of three sequences:
A210998:       4,         8, 9, 10,             14, 15, 16
A000040: 2, 3,    5,    7,          11,     13,
A210999:             6,                 12,
		

Crossrefs

Cf. A002808, A014689, A031215, A031368, A073170, A210999.

Programs

Mathematica

Select[Range[4, 200], Not[PrimeQ[#]] && EvenQ[PrimePi[#]] &] (* Alonso del Arte, Sep 26 2012 *)