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A234099 Integers of the form (p*q*r - 1)/2, where p, q, r are distinct primes. 5
52, 82, 97, 115, 127, 136, 142, 172, 178, 192, 199, 214, 217, 227, 232, 241, 277, 280, 297, 304, 307, 313, 322, 325, 331, 332, 352, 357, 370, 379, 388, 397, 402, 430, 442, 448, 451, 457, 467, 478, 484, 493, 500, 502, 507, 511, 522, 532, 542, 547, 552, 556 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..52.

FORMULA

-1 + A234102.

EXAMPLE

52 = (3*5*7 - 1)/2.

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

Cf. A234100, A234101, A234093, A234102.

Sequence in context: A111173 A090793 A090791 * A026067 A039475 A274338

Adjacent sequences:  A234096 A234097 A234098 * A234100 A234101 A234102

KEYWORD

nonn,easy

AUTHOR

Clark Kimberling, Dec 27 2013

STATUS

approved

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Last modified January 29 11:16 EST 2020. Contains 331337 sequences. (Running on oeis4.)