A153766 -id:A153766 - cp's OEIS frontend

A153767 Primes p such that 8*p - 9 is also prime.

2, 5, 7, 11, 17, 29, 31, 47, 59, 61, 109, 131, 137, 139, 167, 179, 181, 197, 199, 229, 251, 269, 277, 281, 307, 337, 347, 367, 379, 397, 419, 421, 449, 467, 479, 491, 521, 557, 599, 601, 619, 631, 641, 647, 661, 677, 691, 719, 727, 739, 757, 761, 769, 787, 797

Offset: 1

Vincenzo Librandi, Jan 01 2009

			For p=31 (a prime), 8*p - 9 = 239 is also prime, so 31 is in the sequence.

Vincenzo Librandi, Table of n, a(n) for n = 1..3000

Cf. A153766.

[p: p in PrimesUpTo(1000) | IsPrime(8*p-9)]; // Vincenzo Librandi, Apr 04 2013

Select[Prime[Range[150]], PrimeQ[8 # - 9]&] (* Vincenzo Librandi, Apr 04 2013 *)

4 removed, extended by R. J. Mathar, Jan 07 2009

A153768 Numbers n such that n, 8n-9 and 8n+9 are primes.

Original entry on oeis.org

11, 29, 31, 109, 199, 251, 269, 379, 419, 521, 599, 601, 661, 881, 991, 1091, 1231, 1289, 1789, 1831, 1861, 1901, 1949, 2239, 2689, 2969, 3181, 3251, 3301, 3359, 3499, 3779, 3821, 4099, 4201, 4339, 4561, 4651, 4679, 4789, 4871, 5281, 5471, 5641, 5659

Offset: 1

Vincenzo Librandi, Jan 01 2009

			For n=11, even 8n-9=79 and 8n+9=97 are primes, therefore 11 is in the sequence.

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

Cf. A153766, A153767, A153762.

[p: p in PrimesUpTo(6000) | IsPrime(8*p-9) and IsPrime(8*p+9)]; // Vincenzo Librandi, Apr 05 2013

lst={}; Do[p=Prime[n]; If[PrimeQ[8*p-9]&&PrimeQ[8*p+9],AppendTo[lst,p]],{n,7!}]; lst (* Vladimir Joseph Stephan Orlovsky, Aug 16 2009 *)
Select[Prime[Range[6000]], PrimeQ[8 # - 9] && PrimeQ[8 # + 9] &] (* Vincenzo Librandi, Apr 05 2013 *)
Select[Prime[Range[800]],AllTrue[8#+{9,-9},PrimeQ]&] (* Harvey P. Dale, Apr 05 2023 *)

241 replaced by 251 and extended by R. J. Mathar, Jan 07 2009

A153769 Numbers n such that 8n-9 is not prime.

Original entry on oeis.org

0, 1, 3, 6, 8, 9, 12, 13, 15, 16, 18, 19, 21, 23, 24, 27, 28, 30, 32, 33, 36, 37, 38, 39, 41, 42, 43, 44, 45, 48, 50, 51, 52, 53, 54, 57, 58, 60, 63, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 78, 79, 81, 83, 84, 85, 86, 87, 88, 89, 90

Offset: 1

Vincenzo Librandi, Jan 01 2009

			Distribution of the terms > a(2) in the following triangular array:
*;
3,*;
*,*,*;
*,*,9,*;
*,8,*,*,*;
6,*,*,*,19,*;
*,*,*,18,*,*,*;
*,*,16,*,*,*,33,*;
*,13,*,*,*,32,*,*,*;
9,*,*,*,30,*,*,*,51,*;
*,*,*,27,*,*,*,50,*,*,*;
*,*,23,*,*,*,48,*,*,*,73,*;
*,18,*,*,*,45,*,*,*,72,*,*,*;
12,*,*,*,41,*,*,*,70,*,*,*,99,*; etc.
where * marks the non-integer values of (2*h*k + k + h + 5)/4 with h >= k >= 1. - _Vincenzo Librandi_, Jan 19 2013

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

Cf. A153766.

[n: n in [0..100]| not IsPrime(8*n-9)]; // Vincenzo Librandi, Jul 31 2012

lst={};Do[If[!PrimeQ[8*n-9],AppendTo[lst,n]],{n,0, 500}];lst (* Vincenzo Librandi, Jul 31 2012 *)
Select[Range[0,100],!PrimeQ[8#-9]&] (* Harvey P. Dale, Jun 08 2015 *)

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A153767 Primes p such that 8*p - 9 is also prime.

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A153768 Numbers n such that n, 8n-9 and 8n+9 are primes.

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A153769 Numbers n such that 8n-9 is not prime.

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