A274987 Primes p such that A274601(p) is a prime.

3, 5, 7, 11, 13, 17, 23, 31, 37, 53, 59, 61, 73, 79, 83, 89, 101, 103, 109, 127, 137, 139, 149, 173, 179, 193, 223, 229, 257, 263, 293, 307, 313, 337, 347, 349, 359, 367, 389, 397, 409, 419, 439, 449, 461, 467, 487, 491, 521, 547, 571, 577, 599, 601, 619, 631

Offset

1,1

Comments

It is conjectured that the sequence is infinite.

This sequence is also the list of primes with k trits that are used in decomposition of 2*3^k into the sum of such two primes. k>=1.

Links

Lei Zhou, Table of n, a(n) for n = 1..10000

Example

For p=2, A274601(p) = 4, which is not a prime, so ignore 2.
For p=3, A274601(p) = 3, which is a prime, so a(1)=3.
For p=5, A274601(p) = 13, which is a prime, so a(2)=5.

Mathematica

p = 2; Table[While[p = NextPrime[p]; cp = 2*3^(Floor[Log[3, 2*p - 1]]) - p; !PrimeQ[cp]]; p, {n, 1, 56}]

Crossrefs

Cf. A134021, A274601, A002375.

Sequence in context: A176116 A063908 A154868 * A020628 A108816 A088503

Adjacent sequences: A274984 A274985 A274986 * A274988 A274989 A274990

Keyword

nonn,base,easy

Author

Lei Zhou, Nov 11 2016

Status

approved