A023275 -id:A023275 - cp's OEIS frontend

A023305 Primes that remain prime through 4 iterations of function f(x) = 2x + 7.

293, 2063, 4583, 9203, 14723, 20123, 25733, 29453, 40253, 54713, 76103, 97523, 99833, 109433, 138683, 149993, 158243, 196853, 199403, 218873, 253103, 297623, 379913, 416963, 445463, 468113, 508073, 551963, 562403, 564713, 574703, 583733

Offset: 1

David W. Wilson

nonn

Primes p such that 2*p+7, 4*p+21, 8*p+49 and 16*p+105 are also primes. - Vincenzo Librandi, Aug 04 2010

John Cerkan, Table of n, a(n) for n = 1..10000

Subsequence of A023206, A023244, A023275, and A105760.

[n: n in [1..1000000] | IsPrime(n) and IsPrime(2*n+7) and IsPrime(4*n+21) and IsPrime(8*n+49) and IsPrime(16*n+105)] // Vincenzo Librandi, Aug 04 2010

rp4Q[n_]:=AllTrue[Rest[NestList[2#+7&,n,4]],PrimeQ]; Select[Prime[Range[ 50000]],rp4Q] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Mar 30 2020 *)

a(n) == 3 (mod 10). - John Cerkan, Oct 04 2016

A023333 Primes that remain prime through 5 iterations of function f(x) = 2x + 7.

Original entry on oeis.org

14723, 20123, 54713, 109433, 594653, 604883, 676493, 759953, 847103, 935843, 1035743, 1049603, 1079033, 1099823, 1222253, 1263323, 1499153, 1754033, 1835003, 1893173, 2017283, 2071493, 2099213, 2199653, 2895743, 2998313, 3389693, 4133663

Offset: 1

David W. Wilson

nonn

Primes p such that 2*p+7, 4*p+21, 8*p+49, 16*p+105 and 32*p+217 are also primes. - Vincenzo Librandi, Aug 04 2010

John Cerkan, Table of n, a(n) for n = 1..10000

Subsequence of A023206, A023244, A023275, A023305, and A105760.

[n: n in [1..5000000] | IsPrime(n) and IsPrime(2*n+7) and IsPrime(4*n+21) and IsPrime(8*n+49) and IsPrime(16*n+105) and IsPrime(32*n+217)] // Vincenzo Librandi, Aug 04 2010

a(n) == 23 (mod 30). - John Cerkan, Oct 10 2016

cp's OEIS Frontend

A023305 Primes that remain prime through 4 iterations of function f(x) = 2x + 7.

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