A075278 Interprimes which are of the form s*prime, s=3.
6, 9, 15, 21, 39, 69, 93, 111, 129, 309, 381, 393, 453, 489, 501, 687, 723, 771, 879, 933, 939, 1011, 1167, 1299, 1527, 1563, 1569, 1839, 1941, 1983, 2157, 2217, 2229, 2271, 2391, 2463, 2661, 2811, 2859, 2913, 3039, 3099, 3189, 3453, 3459, 3651, 3849
Offset: 1
Examples
39 is an interprime and 39/3 = 13 is prime.
Programs
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Mathematica
s=3; Select[Table[(Prime[n+1]+Prime[n])/2, {n, 2, 1000}], PrimeQ[ #/s]&]
Comments