A062894 The prime indices of sequence A067836 (that sequence is conjectured to contain only primes).

1, 2, 3, 4, 6, 5, 7, 8, 9, 12, 21, 10, 11, 14, 22, 16, 23, 19, 13, 15, 41, 35, 42, 27, 20, 17, 45, 39, 29, 33, 28, 54, 26, 37, 46, 61, 47, 59, 40, 31, 57, 18, 24, 58, 36, 43, 49, 64, 80, 106, 67, 60, 65, 63, 48, 94, 85, 51, 73, 122, 105, 100, 113, 138, 104, 115, 75, 32, 82

Offset

1,2

Links

Robert Price, Table of n, a(n) for n = 1..1000

Example

a(12)=10 because a(12) in sequence A067836 is 29, which is the 10th prime number.

Mathematica

Join[{1}, a = 2; f = 1; Table[f = f*a; a = NextPrime[f + 1] - f; k = 1; While[Prime[k] != a, k++]; k, {n, 2, 69}]] (* Jayanta Basu, Aug 10 2013 *)

Prog

(Python)
from sympy import primepi, nextprime
def A062894_gen(): # generator of terms
    a, f = 2, 1
    yield 1
    while True:
        yield primepi(a:=nextprime((f:=f*a)+1)-f)
A062894_list = list(islice(A062894_gen(), 30)) # Chai Wah Wu, Sep 09 2023

Crossrefs

Cf. A067836.

Sequence in context: A275659 A244321 A364824 * A339723 A129606 A057510

Adjacent sequences: A062891 A062892 A062893 * A062895 A062896 A062897

Keyword

nonn

Author

Frank Buss (fb(AT)frank-buss.de), Feb 13 2002

Extensions

Edited by Dean Hickerson, Jun 10 2002

Status

approved