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A154732 Integers n such that (n^3 + n^2) -+ 1 are primes. 1
2, 5, 9, 11, 12, 26, 44, 47, 62, 69, 71, 89, 125, 140, 147, 179, 219, 254, 264, 285, 294, 312, 317, 326, 341, 344, 384, 407, 461, 495, 659, 680, 714, 740, 837, 845, 861, 866, 867, 957, 989, 1071, 1079, 1152, 1215, 1310, 1437, 1481, 1499, 1511, 1530, 1577 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

2^3 + 2^2 = 12 -+ 1 = 11 and 13 (both prime).

LINKS

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

MATHEMATICA

lst={}; Do[k=n^3+n^2; If[PrimeQ[k-1]&&PrimeQ[k+1], AppendTo[lst, n]], {n, 8!}]; lst

Select[Range[3000], PrimeQ[#^3 + #^2 - 1] && PrimeQ[#^3 + #^2 + 1] &] (* Vincenzo Librandi, Dec 26 2015 *)

PROG

(MAGMA) [n: n in [1..5*10^3] |IsPrime(n^3+n^2-1) and IsPrime(n^3+n^2+1)]; // Vincenzo Librandi, Dec 26 2015

(PARI) isok(n) = isprime(n^3+n^2+1) && isprime(n^3+n^2-1); \\ Michel Marcus, Dec 27 2015

CROSSREFS

Cf. A111503, A154731.

Sequence in context: A005123 A283481 A284875 * A242936 A080154 A069829

Adjacent sequences:  A154729 A154730 A154731 * A154733 A154734 A154735

KEYWORD

nonn,easy

AUTHOR

Vladimir Joseph Stephan Orlovsky, Jan 14 2009

STATUS

approved

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Last modified October 15 03:16 EDT 2019. Contains 328025 sequences. (Running on oeis4.)