A120227 -id:A120227 - cp's OEIS frontend

A120226 Numbers k such that 4+k and 4*k+1 are prime.

1, 3, 7, 9, 13, 15, 25, 27, 37, 39, 43, 49, 57, 67, 69, 79, 93, 97, 99, 105, 127, 135, 153, 163, 169, 175, 177, 189, 193, 207, 219, 235, 253, 265, 267, 273, 277, 279, 303, 307, 309, 343, 345, 363, 405, 417, 427, 435, 475, 483, 487, 499, 517, 553, 559, 567, 573

Offset: 1

Zak Seidov, Jun 10 2006

nonn

Except for 3, no terms == 3 or 5 (mod 7). - Robert Israel, Jul 26 2019

Robert Israel, Table of n, a(n) for n = 1..10000

Cf. A092945, A106057, A085063, A120223, A120224, A120225, A120227.

select(t -> isprime(t+4) and isprime(4*t+1), [seq(i,i=1..1000,2)]); # Robert Israel, Jul 26 2019

Select[Range[600],AllTrue[{4+#,4#+1},PrimeQ]&] (* Harvey P. Dale, Nov 14 2022 *)

A120222 Numbers k such that 6+k and 6*k+1 are prime.

Original entry on oeis.org

1, 5, 7, 11, 13, 17, 23, 25, 35, 37, 47, 55, 61, 73, 77, 83, 91, 95, 101, 103, 107, 121, 125, 131, 143, 151, 161, 173, 175, 187, 205, 217, 221, 233, 245, 257, 263, 271, 277, 287, 305, 311, 325, 331, 347, 367, 373, 391, 395, 425, 443, 451, 455, 461, 481, 503, 551

Offset: 1

Zak Seidov, Jun 10 2006

nonn

All terms == 1 or 5 (mod 6). - Robert Israel, Oct 29 2020

Robert Israel, Table of n, a(n) for n = 1..10000

Cf. A120226, A120227, A120228, A106057-A106066.

select(n -> isprime(n+6) and isprime(6*n+1), [seq(i,i=1..1000,2)]); # Robert Israel, Oct 29 2020

Select[Range[551],PrimeQ[#+6]&&PrimeQ[6#+1]&] (* James C. McMahon, Sep 26 2024 *)

A120228 Numbers k such that 8+k and 8*k+1 are prime.

Original entry on oeis.org

5, 9, 11, 29, 35, 39, 51, 65, 71, 75, 95, 101, 119, 129, 131, 141, 149, 165, 185, 215, 219, 225, 249, 261, 269, 285, 299, 305, 309, 329, 339, 341, 371, 375, 381, 401, 431, 441, 449, 459, 471, 479, 491, 555, 591, 599, 611, 635, 639, 651, 711, 725, 731, 735, 761

Offset: 1

Zak Seidov, Jun 10 2006

nonn

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Cf. A106057-A106066, A120222, A120226, A120227.

Select[Range[800],AllTrue[{8+#,8#+1},PrimeQ]&] (* Harvey P. Dale, May 28 2016 *)

cp's OEIS Frontend

A120226 Numbers k such that 4+k and 4*k+1 are prime.

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A120222 Numbers k such that 6+k and 6*k+1 are prime.

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Maple

Mathematica

A120228 Numbers k such that 8+k and 8*k+1 are prime.

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Mathematica