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A305033
Numbers m such that m + k# is a prime, where k = floor(sqrt(m)) and k# is the primorial A034386(k).
0
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.
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
KEYWORD
nonn
AUTHOR
STATUS
approved