A222565 Primes that are the largest anti-divisor of primes.

2, 3, 5, 7, 11, 13, 19, 29, 31, 41, 47, 53, 59, 67, 71, 73, 101, 109, 127, 131, 149, 151, 167, 179, 181, 211, 233, 239, 281, 293, 307, 311, 347, 349, 379, 401, 409, 421, 431, 439, 449, 461, 467, 479, 541, 547, 569, 571, 587, 607, 613, 619, 631, 647, 661, 673, 701

Offset: 1

Author

Juri-Stepan Gerasimov, Feb 25 2013

Keywords

• nonn

Comments

See A066272 for definition of anti-divisor.

Primes p such that 2p + largest anti-divisor of 2p is also prime: 2, 5, 7, 11, 13, 29, 31, 41, 47, 59, 67, 79, 83, 101, 137, 139, 151, 157, 167, 173, 193, 223, 227, 239, 257,...

Examples

			The prime 19 is here because it is largest anti-divisor of prime 29.
		

Links

• Paolo P. Lava, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A066481.

Programs

PARI

is(n)=isprime(n)&&isprime(bitor((3*n-1)\2,1)) \\ Charles R Greathouse IV, Feb 27 2013

Formula

2 together with primes of the form 4k+1 such that 6k+1 is prime, together with primes of the form 4k+3 such that 6k+5 is prime. - Charles R Greathouse IV, Feb 27 2013

Extensions

Missing terms a(9), a(21), a(28), a(29) added by Charles R Greathouse IV, Feb 27 2013