A157977 -id:A157977 - cp's OEIS frontend

A157978 Primes p such that 4*p - 3 is also a prime.

2, 5, 11, 19, 23, 29, 59, 61, 71, 79, 89, 101, 103, 109, 113, 131, 149, 151, 191, 193, 233, 239, 263, 283, 313, 331, 353, 359, 373, 389, 401, 431, 439, 479, 499, 521, 523, 541, 569, 571, 599, 619, 631, 653, 659, 673, 683, 701, 709, 739, 743, 751, 761, 773, 829

Offset: 1

Vladimir Joseph Stephan Orlovsky, Mar 10 2009

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

Cf. A136082, A136083, A023213, A023221, A023235, A023240, A157974, A136083, A136084, A136085, A136086, A136087, A089440, A157975, A157976, A157977.

[n: n in [0..2000] | IsPrime(n) and IsPrime(4*n - 3)]; // Vincenzo Librandi, Feb 03 2014

q=3;lst={};Do[p=Prime[n];If[PrimeQ[(q+1)*p-q],AppendTo[lst,p]],{n,6!}];lst
Select[Prime[Range[1000]],PrimeQ[4 # - 3]&] (* Vincenzo Librandi, Feb 03 2014 *)

A167464 Primes p such that 20*p+19 is composite.

Original entry on oeis.org

5, 7, 13, 19, 31, 37, 43, 47, 53, 59, 61, 67, 73, 79, 83, 89, 97, 103, 107, 109, 113, 127, 131, 137, 139, 151, 157, 163, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 241, 257, 271, 277, 283, 307, 311, 313, 331, 337, 349, 359, 367, 373, 379, 383, 389

Offset: 1

Vincenzo Librandi, Nov 04 2009

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

Cf. A157977.

[p: p in PrimesUpTo(400) | not IsPrime(20*p+19)]; // Vincenzo Librandi, Feb 15 2014

Select[Prime[Range[500]], !PrimeQ[20 # + 19] &]
(* Vincenzo Librandi, Feb 15 2014 *)

cp's OEIS Frontend

A157978 Primes p such that 4*p - 3 is also a prime.

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