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A241716 Primes p such that p^3 - 2 is semiprime. 2
2, 3, 5, 7, 11, 13, 17, 41, 43, 47, 61, 79, 89, 101, 107, 139, 157, 181, 199, 239, 271, 307, 311, 331, 337, 347, 349, 379, 397, 409, 421, 431, 479, 487, 499, 521, 523, 541, 571, 607, 613, 641, 643, 661, 673, 701, 719, 761, 769, 811, 823, 829, 839, 877, 881, 883 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
EXAMPLE
11 is prime and appears in the sequence because 11^3 - 2 = 1329 = 3 * 443, which is a semiprime.
17 is prime and appears in the sequence because 17^3 - 2 = 4911 = 3 * 1637, which is a semiprime.
23 is prime but does not appear in the sequence because 23^3 - 2 = 12165 = 3 * 5 * 811, which is not a semiprime.
MAPLE
with(numtheory):A241716:= proc() local k; k:=ithprime(x); if bigomega(k^3-2)=2 then RETURN (k); fi; end: seq(A241716(), x=1..500);
MATHEMATICA
A241716 = {}; Do[t = Prime[n]; If[PrimeOmega[t^3 - 2] == 2, AppendTo[A241716, t]], {n, 500}]; A241716
Select[Prime[Range[200]], PrimeOmega[#^3-2]==2&] (* Harvey P. Dale, Dec 09 2018 *)
CROSSREFS
Sequence in context: A258706 A265408 A053434 * A061166 A003681 A217147
KEYWORD
nonn
AUTHOR
K. D. Bajpai, Apr 27 2014
STATUS
approved

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Last modified May 20 11:46 EDT 2024. Contains 372712 sequences. (Running on oeis4.)