A275991 a(n) = prime(composite(n)) - prime(n).

5, 10, 14, 16, 18, 24, 26, 28, 30, 32, 40, 36, 38, 46, 50, 48, 44, 46, 46, 60, 64, 60, 66, 62, 66, 66, 70, 74, 84, 84, 72, 92, 90, 90, 84, 88, 94, 94, 96, 96, 92, 100, 102, 114, 114, 114, 106, 114, 120, 120, 126, 134, 138, 132, 132, 134, 140, 148, 144, 152, 156, 150

Offset: 1

Author

Terry D. Grant, Aug 15 2016

Keywords

• nonn
• changed

Examples

			For n=3, prime(composite(3)) = 19, and prime(3) = 5, therefore a(3) = 19 - 5 = 14.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A088982.

Programs

Mathematica

Module[{nn=100,cmps},cmps=Select[Range[nn],CompositeQ];Prime[cmps]-Prime[Range[Length[cmps]]]] (* Harvey P. Dale, Sep 02 2025 *)

Formula

a(n) = A000040(A002808(n)) - A000040(n) = A088982(n) - A000040(n).

Extensions

Previous Mathematica program replaced by Harvey P. Dale, Sep 02 2025