A349722 Primes p such that the greatest common divisor of 2^p+1 and 3^p+1 is composite.

2243399, 2334547, 2743723, 3932207, 4623107, 4716343, 5482423, 5993411, 6490151, 7156769, 7187743, 8795167, 9026987, 9608843, 9923209

Offset

1,1

Links

Table of n, a(n) for n=1..15.

Carlos Rivera, Puzzle 1064. GCD(2^p+1,3^p+1), The Prime Puzzles and Problems Connection.

Prog

(PARI) isok(p) = if (isprime(p), my(g=gcd(2^p+1, 3^p+1)); (g>1) && !isprime(g));

Crossrefs

Subsequence of A260674.

Cf. A066803.

Sequence in context: A224629 A224636 A046444 * A180940 A089445 A089446

Adjacent sequences: A349719 A349720 A349721 * A349723 A349724 A349725

Keyword

nonn,more

Author

Michel Marcus, Nov 27 2021

Extensions

a(4)-a(7) after update of Rivera link from Martin Ehrenstein, Dec 04 2021

a(8)-a(9) from Shyam Sunder Gupta, Dec 04 2021

a(10)-a(15) from Martin Ehrenstein, Dec 05 2021

Status

approved