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A161863 Numbers n such that n^2+n+3 and n^2+n-3 are both prime. 2
4, 7, 10, 22, 25, 34, 70, 79, 112, 130, 139, 172, 187, 217, 229, 262, 274, 295, 304, 322, 337, 364, 397, 400, 472, 499, 574, 580, 592, 622, 634, 655, 664, 697, 829, 844, 925, 1057, 1144, 1165, 1255, 1300, 1309, 1357, 1414, 1420, 1489, 1537, 1642, 1669, 1744 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..51.

EXAMPLE

n=4 is in the list because 20+-3 are primes. n=7 is in the list because 56+-3 are primes.

MATHEMATICA

q=3; lst3={}; Do[p=n^2+n; If[PrimeQ[p-q]&&PrimeQ[p+q], AppendTo[lst3, n]], {n, 0, 7!}]; lst3

CROSSREFS

Cf. A088485

Sequence in context: A111981 A080922 A227686 * A102649 A084386 A275176

Adjacent sequences:  A161860 A161861 A161862 * A161864 A161865 A161866

KEYWORD

nonn,easy

AUTHOR

Vladimir Joseph Stephan Orlovsky, Jun 20 2009

EXTENSIONS

Definition rephrased by R. J. Mathar, Jun 27 2009

STATUS

approved

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Last modified May 20 20:16 EDT 2019. Contains 323426 sequences. (Running on oeis4.)