A305033 Numbers m such that m + k# is a prime, where k = floor(sqrt(m)) and k# is the primorial A034386(k).

1, 2, 5, 11, 13, 17, 23, 29, 31, 37, 41, 43, 53, 59, 61, 67, 71, 73, 83, 97, 101, 103, 107, 127, 131, 137, 149, 157, 163, 167, 173, 181, 193, 211, 223, 229, 239, 241, 263, 277, 283, 293, 307, 313, 317, 337, 373, 383, 389, 409, 421, 449, 457, 463, 479, 523, 541

Offset

1,2

Comments

Since every composite number m is divisible by a prime p <= sqrt(m), the sequence contains only noncomposite numbers.

Links

Table of n, a(n) for n=1..57.

Index to divisibility sequences

Index entries for sequences computed from indices in prime factorization

Prog

(PARI) v=0; for(n=1, 541, pp=primepi(sqrtint(n)); if(pp>v, v=pp); if(isprime(n+factorback(primes(v))), print1(n, ", ")));

Crossrefs

Cf. A034386.

Sequence in context: A218582 A118753 A337649 * A066149 A215423 A019387

Adjacent sequences: A305030 A305031 A305032 * A305034 A305035 A305036

Keyword

nonn

Author

Arkadiusz Wesolowski, May 24 2018

Status

approved