The On-Line Encyclopedia of Integer Sequences (OEIS)

A024898 revision #44

A024898

Positive integers k such that 6k - 1 is prime.

1, 2, 3, 4, 5, 7, 8, 9, 10, 12, 14, 15, 17, 18, 19, 22, 23, 25, 28, 29, 30, 32, 33, 38, 39, 40, 42, 43, 44, 45, 47, 49, 52, 53, 58, 59, 60, 64, 65, 67, 70, 72, 74, 75, 77, 78, 80, 82, 84, 85, 87, 93, 94, 95, 98, 99, 100, 103, 107, 108, 109, 110, 113, 114, 117, 120, 124, 127, 129, 133

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OFFSET

1,2

COMMENTS

Actual primes are A007528.

For each number k in this sequence, there are no positive integers (x,y) such that k = 6xy + x - y. - Pedro Caceres, Jan 22 2018

Number of terms less than 10^r, r=1,2,3,...: 8, 56, 397, 3040, 24571, 206502, 1781237, ... - Muniru A Asiru, Jan 26 2018

LINKS

Zak Seidov and Michael De Vlieger, Table of n, a(n) for n = 1..10000 (first 3000 terms from Zak Seidov)

MAPLE

select(k -> isprime(6*k-1), [$1..10^3]); # Muniru A Asiru, Jan 26 2018

MATHEMATICA

Select[Range[150], PrimeQ[6 # - 1] &] (* Bruno Berselli, Jul 14 2014 *)

PROG

(MAGMA) [n: n in [0..1000]| IsPrime(6*n-1)]; // Vincenzo Librandi, Nov 20 2010

(GAP) Filtered([1..1000], k->IsPrime(6*k-1)); # Muniru A Asiru, Jan 26 2018

CROSSREFS

Cf. A007528, A046953 (complement).

Sequence in context: A099849 A071163 A006644 * A094210 A165256 A175020

Adjacent sequences: A024895 A024896 A024897 * A024899 A024900 A024901

KEYWORD

nonn

AUTHOR

Clark Kimberling

STATUS

editing