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A154939 Primes p such that (p-1)*(p+1)-+p are primes. 9
3, 5, 11, 31, 101, 131, 149, 181, 241, 331, 419, 449, 709, 1051, 1061, 1171, 1409, 1549, 1579, 1699, 1759, 1831, 2069, 3229, 3449, 3761, 3911, 4159, 4951, 5821, 6029, 6481, 6661, 6679, 6899, 7079, 7151, 7229, 7369, 8101, 8219, 8629, 8861, 9091, 9161, 9521 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

That is, primes p such that p^2+p-1 and p^2-p-1 are both primes: intersection of A053184 and A091567. - Michel Marcus, Jul 10 2016

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

EXAMPLE

2*4=8-+3 -> primes, 4*6=24-+5 -> primes,...

MATHEMATICA

lst={}; Do[p=Prime[n]; If[PrimeQ[(p-1)*(p+1)-p]&&PrimeQ[(p-1)*(p+1)+p], AppendTo[lst, p]], {n, 7!}]; lst

Select[Prime[Range[1500]], And@@PrimeQ/@{#^2 - # - 1, #^2 + # - 1} &] (* Vincenzo Librandi, Jul 10 2016 *)

PROG

(MAGMA) [p: p in PrimesUpTo(10000) | IsPrime(p^2+p-1) and IsPrime(p^2-p-1)]; // Vincenzo Librandi, Jul 10 2016

CROSSREFS

Cf. A053184, A038872, A141158, A091567, A098058, A038936, A089270, A140559.

Sequence in context: A236568 A095184 A048235 * A121926 A063499 A285381

Adjacent sequences:  A154936 A154937 A154938 * A154940 A154941 A154942

KEYWORD

nonn

AUTHOR

Vladimir Joseph Stephan Orlovsky, Jan 17 2009

STATUS

approved

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Last modified February 25 12:01 EST 2020. Contains 332233 sequences. (Running on oeis4.)