A075282 Interprimes which are of the form s*prime, s=7.

21, 217, 2191, 2933, 3073, 3353, 7063, 7091, 8813, 9079, 9233, 9527, 9569, 10493, 10717, 11851, 12131, 16667, 17857, 18263, 18347, 19243, 19733, 22421, 23093, 24703, 24787, 25417, 27349, 28637, 32347, 32473, 33607, 33691, 35273, 35413

Offset: 1

Author

Zak Seidov, Sep 12 2002

Keywords

• easy
• nonn

Comments

Interprimes which are of the form s*prime are in A075277-A075296 (s = 2-21). Case s = 1 is impossible.

Examples

			2191 is an interprime and 2191/7 = 317 is prime.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A075277-A075296.

Programs

Mathematica

s=7; Select[Table[(Prime[n+1]+Prime[n])/2, {n, 2, 1000}], PrimeQ[ #/s]&]
Select[Mean/@Partition[Prime[Range[4000]],2,1],PrimeQ[#/7]&] (* Harvey P. Dale, Jul 13 2025 *)