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Interprimes which are of the form s*prime, s=7.
0

%I #6 Mar 30 2012 17:26:03

%S 21,217,2191,2933,3073,3353,7063,7091,8813,9079,9233,9527,9569,10493,

%T 10717,11851,12131,16667,17857,18263,18347,19243,19733,22421,23093,

%U 24703,24787,25417,27349,28637,32347,32473,33607,33691,35273,35413

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

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

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

%t s=7; Select[Table[(Prime[n+1]+Prime[n])/2, {n, 2, 1000}], PrimeQ[ #/s]&]

%Y Cf. A075277-A075296.

%K easy,nonn

%O 1,1

%A _Zak Seidov_, Sep 12 2002