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A234101
Primes of the form (p*q*r - 1)/2, where p, q, r are distinct primes.
4
97, 127, 199, 227, 241, 277, 307, 313, 331, 379, 397, 457, 467, 547, 617, 619, 647, 709, 727, 739, 757, 773, 797, 829, 883, 977, 1033, 1069, 1117, 1123, 1171, 1193, 1277, 1297, 1303, 1319, 1423, 1447, 1459, 1483, 1609, 1621, 1667, 1697, 1699, 1747, 1753
OFFSET
1,1
EXAMPLE
(See A234100.)
MATHEMATICA
t = Select[Range[1, 10000, 2], Map[Last, FactorInteger[#]] == Table[1, {3}] &]; Take[(t - 1)/2, 120] (* A234099 *)
v = Flatten[Position[PrimeQ[(t - 1)/2], True]] ; w = Table[t[[v[[n]]]], {n, 1, Length[v]}] (* A234100 *)
(w - 1)/2 (* A234101 *) (* Peter J. C. Moses, Dec 23 2013 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Dec 27 2013
STATUS
approved