A156287 -id:A156287 - cp's OEIS frontend

A156288 Numbers n such that 4*n-5 is not a prime number.

5, 8, 10, 11, 14, 15, 17, 20, 23, 24, 25, 26, 29, 30, 31, 32, 35, 37, 38, 40, 41, 44, 45, 47, 48, 50, 52, 53, 55, 56, 59, 60, 62, 63, 65, 66, 68, 70, 71, 73, 74, 75, 76, 77, 80, 81, 82, 83, 85, 86, 87, 89, 90, 92, 94, 95, 98, 99, 100, 101, 102, 103, 104, 105, 107, 108, 110

Offset: 1

Vincenzo Librandi, Feb 07 2009

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

Cf. A156287.

[n: n in [2..150] | not IsPrime(4*n-5)]; // Vincenzo Librandi, Apr 06 2013

Select[Range[2, 150], !PrimeQ[4 # - 5]&] (* Vincenzo Librandi, Apr 06 2013 *)

A156300 Primes p such that 4*p - 5 is also prime.

Original entry on oeis.org

2, 3, 7, 13, 19, 43, 61, 67, 79, 97, 109, 127, 151, 163, 181, 211, 223, 229, 277, 307, 331, 373, 379, 397, 457, 463, 523, 601, 607, 613, 673, 727, 733, 751, 757, 853, 883, 907, 919, 967, 1021, 1033, 1069, 1117, 1171, 1201, 1231, 1237, 1321, 1327, 1381, 1399

Offset: 1

Vincenzo Librandi, Feb 07 2009

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

Cf. A156287, A156288.

[p: p in PrimesUpTo(1400) | IsPrime(4*p - 5)]; // Vincenzo Librandi, Oct 31 2012

Select[Prime[Range[1400]], PrimeQ[(4# - 5)]&] (* Vincenzo Librandi, Oct 31 2012 *)

cp's OEIS Frontend

A156288 Numbers n such that 4*n-5 is not a prime number.

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