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A234502
Primes of the form (p*q*r*s + 1)/2, where p, q, r, s are distinct primes.
3
683, 1523, 2153, 2243, 2393, 2423, 2503, 2657, 3023, 3203, 3581, 3833, 4133, 4373, 4583, 4673, 4967, 5003, 5051, 5233, 5273, 5303, 5483, 5653, 5843, 6221, 6299, 6793, 7193, 7211, 7487, 7523, 7703, 7823, 7937, 8093, 8243, 8543, 8693, 9323, 9377, 9461, 9533
OFFSET
1,1
EXAMPLE
(See A234501.)
MATHEMATICA
t = Select[Range[1, 20000, 2], Map[Last, FactorInteger[#]] == Table[1, {4}] &]; Take[(t + 1)/2, 120] (* A234500 *)
v = Flatten[Position[PrimeQ[(t + 1)/2], True]] ; w = Table[t[[v[[n]]]], {n, 1, Length[v]}] (* A234501 *)
(w + 1)/2 (* A234502 *) (* Peter J. C. Moses, Dec 23 2013 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Jan 01 2014
STATUS
approved