A135731 a(1) = 3; thereafter a(n+1) = a(n) + nextprime(a(n)) - prevprime(a(n)).

3, 6, 8, 12, 14, 18, 20, 24, 30, 32, 38, 42, 44, 48, 54, 60, 62, 68, 72, 74, 80, 84, 90, 98, 102, 104, 108, 110, 114, 128, 132, 138, 140, 150, 152, 158, 164, 168, 174, 180, 182, 192, 194, 198, 200, 212, 224, 228, 230, 234, 240, 242, 252, 258, 264, 270, 272, 278

Offset: 1

Author

Enoch Haga, Nov 26 2007

Keywords

• easy
• nonn

Comments

Essentially the same as A008864. [From R. J. Mathar, Oct 28 2008]

Only the first term is prime, the rest are even, and between any pair of adjacent terms a(n) and a(n+1), there is just one prime, namely prime(n+2). - David James Sycamore, Dec 07 2018

Examples

			a(1) = 3, so a(2) = 3 + (5-2)  = 6,
a(3) = 6 + (7-5) = 8,
a(4) = 8 + (11-7) = 12; etc.
		

Links

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

Crossrefs

Cf. A001223, A008864, A135732.

Programs

Mathematica

NestList[#+NextPrime[#]-NextPrime[#,-1]&,3,60] (* Harvey P. Dale, Oct 13 2024 *)

Formula

a(n+1) = a(n) + A001223(n+1) for n>1. - David James Sycamore, Dec 07 2018

Extensions

Definition corrected and entry revised by David James Sycamore, Dec 07 2018