A169606 a(2n-1) = prime(n+2)-3, a(2n) = prime(n+2)-2.

2, 3, 4, 5, 8, 9, 10, 11, 14, 15, 16, 17, 20, 21, 26, 27, 28, 29, 34, 35, 38, 39, 40, 41, 44, 45, 50, 51, 56, 57, 58, 59, 64, 65, 68, 69, 70, 71, 76, 77, 80, 81, 86, 87, 94, 95, 98, 99, 100, 101, 104, 105, 106, 107, 110, 111, 124, 125, 128, 129, 134, 135, 136, 137, 146

Offset: 1

Author

Juri-Stepan Gerasimov, Dec 03 2009

Keywords

• nonn
• easy

Examples

			a(1)=5-3=2; a(2)=5-2=3; a(3)=7-3=4.
		

Links

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

Crossrefs

Cf. A047247, A000040.

Programs

Mathematica

Table[If[OddQ[n],Prime[(n+1)/2+2]-3,Prime[n/2+2]-2],{n,70}] (* Harvey P. Dale, Oct 25 2020 *)

PARI

forprime(p=5,97,print1(p-3", "p-2", ")) \\ Charles R Greathouse IV, May 25 2011

Formula

a(n) ~ 0.5 n log n. - Charles R Greathouse IV, May 25 2011

Extensions

Entries checked by R. J. Mathar, Apr 14 2010

Definition reworded by N. J. A. Sloane, Aug 24 2012