A093502 a(1) = 2; for n > 0, a(n+1) is the a(n)-th prime after a(n).

2, 5, 19, 103, 733, 6691, 76831, 1081429, 18242699, 361919671, 8309068723, 217809953467, 6445388418589, 213232943658197, 7821073506524401, 315743571062703689

Offset

1,1

Links

Table of n, a(n) for n=1..16.

Formula

a(n) = prime(pi(a(n-1)) + a(n-1)). - Vladeta Jovovic, Jun 19 2004

a(1)=2, a(n) = next a(n-1)th prime after a(n-1). - Zak Seidov, Mar 21 2009

a(n+1) = A000040(a(n) + index of a(n) in A000040). - David James Sycamore, Aug 20 2017

Example

19 follows 5 as there are 5 primes > 5 and up to 19 inclusive, (7,11,13,17,19).

Mathematica

a[1] := 2; a[n_] := Prime[PrimePi[a[n - 1]] + a[n - 1]]; Table[a[n], {n, 1, 10}] (* Stefan Steinerberger, Apr 10 2006 *)
NestList[Prime[PrimePi[ # ] + # ] &, 2, 13] (* Zak Seidov, Mar 21 2009 *)

Prog

(Python)
from sympy import prime
p, q = 2, 1
A093502_list = [p]
for _ in range(15):
    r = p + q
    p, q = prime(r), r
    A093502_list.append(p) # Chai Wah Wu, Jun 17 2019

Crossrefs

Sequence in context: A020117 A054687 A076669 * A009311 A211207 A107882

Adjacent sequences: A093499 A093500 A093501 * A093503 A093504 A093505

Keyword

more,nonn

Author

Amarnath Murthy, Apr 17 2004

Extensions

a(10) from Vladeta Jovovic, Jun 19 2004

More terms from Stefan Steinerberger, Apr 10 2006

a(13) from Zak Seidov, Mar 21 2009

a(14)-a(15) from Donovan Johnson, Dec 08 2009

Better definition from Jon E. Schoenfield, Aug 22 2017

a(16) from Chai Wah Wu, Jun 17 2019

Status

approved