A094068 Lessers of twin prime pairs whose greater has a prime prime index.

3, 29, 107, 239, 281, 857, 1061, 1151, 1619, 1667, 1721, 2267, 2339, 2801, 2999, 3167, 3257, 3467, 3557, 4271, 4337, 4547, 4799, 4931, 5279, 5501, 5849, 5867, 6359, 6659, 6689, 7349, 8009, 8219, 8231, 8387, 9857, 10007, 10859, 13001, 13691, 15269, 15971

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Example

107 is the lesser of twin prime pair (107,109) the prime index of 109 (the greater) is 29.

Mathematica

seq = {}; p = prv = 2; k = 1; Do[p = NextPrime[p]; k++; If[p == prv + 2 && PrimeQ[k], AppendTo[seq, prv]]; prv = p, {10^3}]; seq
Select[Partition[Prime[Range[2000]], 2, 1], #[[2]]-#[[1]]==2&&PrimeQ[PrimePi[ #[[2]]]]&] [[All, 1]] (* Harvey P. Dale, Nov 30 2022 *)

Prog

(PARI) lista(n) = {forprime(x=2, n, y=prime(x)- 2; if(isprime(y), print1(y", ")))}

Crossrefs

Cf. A001097, A001359, A006512, A096479.

Sequence in context: A106942 A211621 A100202 * A084105 A024386 A171355

Adjacent sequences: A094065 A094066 A094067 * A094069 A094070 A094071

Keyword

nonn

Author

Cino Hilliard, May 31 2004

Extensions

Offset corrected by Amiram Eldar, Dec 27 2019

Status

approved