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
Links
- Carlos Rivera, Puzzle 1064. GCD(2^p+1,3^p+1), The Prime Puzzles and Problems Connection.
Programs
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PARI
isok(p) = if (isprime(p), my(g=gcd(2^p+1, 3^p+1)); (g>1) && !isprime(g));
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