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A291319 Squarefree triprimes of the form p*q*r such that p+q+r-1 is prime. 2
42, 70, 78, 110, 114, 130, 154, 170, 222, 230, 258, 310, 322, 370, 374, 402, 406, 410, 418, 442, 470, 474, 530, 582, 598, 610, 618, 638, 646, 654, 670, 682, 730, 742, 754, 762, 782, 826, 830, 874, 902, 970, 978, 986, 994, 1010, 1030, 1034, 1070, 1158, 1222 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

EXAMPLE

42 = 2*3*7 and 2+3+7-1 is prime, so 42 is a term.

418 = 2*11*19 and 2+11+19-1 is prime, so 418 is a term.

MATHEMATICA

With[{nnn=80}, Take[Times@@@Select[Subsets[Prime[Range[nnn]], {3}], PrimeQ[Total[#] - 1] &]//Union, nnn]]

PROG

(PARI) list(lim)=my(v=List()); forprime(p=5, lim\6, forprime(q=3, min(lim\2\p, p-2), if(isprime(p+q+1), listput(v, 2*p*q)))); Set(v) \\ Charles R Greathouse IV, Aug 23 2017

CROSSREFS

Subsequence of A007304.

Sequence in context: A115957 A255989 A192274 * A226168 A248430 A305153

Adjacent sequences:  A291316 A291317 A291318 * A291320 A291321 A291322

KEYWORD

nonn,easy

AUTHOR

Vincenzo Librandi, Aug 23 2017

STATUS

approved

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Last modified October 19 12:10 EDT 2019. Contains 328219 sequences. (Running on oeis4.)