A028815 a(n) = prime(n) + 1 (starting with 1).

2, 3, 4, 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, 282, 284

Offset

0,1

Comments

n-th noncomposite (unit or prime) positive integer + 1.

The "0th prime" is defined to be 1 (a unit, formerly considered to be prime).

Links

G. C. Greubel, Table of n, a(n) for n = 0..10000

Formula

a(n) = prime(n) + 1 = A000040(n) + 1 = A008864(n) for n >= 1.

a(n) = A008578(n+1) + 1, n >= 0.

a(n) = 2*A006254(n-1), for n >= 2, with a(0) = 2, a(1) = 3. - G. C. Greubel, Aug 05 2024

Mathematica

Join[{2}, Prime[Range[70]]+1] (* Harvey P. Dale, Oct 14 2019 *)

Prog

(PARI) a(n) = if(n==0, 2, prime(n) + 1); \\ Altug Alkan, Mar 14 2018
(Magma)
A028815:= func< n | n eq 0 select 2 else 1 + NthPrime(n) >;
[A028815(n): n in [0..70]]; // G. C. Greubel, Aug 05 2024
(SageMath)
def A028815(n): return 2 if n==0 else 1+nth_prime(n)
[A028815(n) for n in range(71)] # G. C. Greubel, Aug 05 2024

Crossrefs

Cf. A000040, A006093, A008578, A008864.

Cf. A141130, A141132, A141133, A141136, A141138.

Sequence in context: A336503 A275717 A029449 * A014423 A101902 A236912

Adjacent sequences: A028812 A028813 A028814 * A028816 A028817 A028818

Keyword

nonn,easy

Author

N. J. A. Sloane

Status

approved