A333721 Numbers k such that k + 1, 2k + 1, 3k + 1, 4k + 1, and 6k + 1 are all prime.

1530, 4260, 25410, 26040, 78540, 111720, 174990, 211050, 214830, 395430, 403260, 409290, 459690, 487830, 512820, 711120, 779790, 910560, 1023750, 1135950, 1280370, 1312350, 1451520, 1464810, 1487070, 1563510, 1623360, 1698060, 1824330, 1933680, 2006340, 2097480

Offset

1,1

Comments

All terms are multiples of 6.

All terms are multiples of 30. - Robert Israel, Jun 17 2020

Links

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

Pedro Caceres, 30 Ideas about Prime Numbers

Example

25410 is in the sequence because 25411, 50821, 76231, 101641, 152461 are all prime.

Maple

select(t -> andmap(isprime, [t+1, 2*t+1, 3*t+1, 4*t+1, 6*t+1]), [seq(i, i=30..3*10^6, 30)]); # Robert Israel, Jun 17 2020

Prog

(PARI)
isok(m)={for(i=1, 6, if(i<>5&&!isprime(i*m+1), return(0))); 1}
{ forstep(n=0, 3*10^6, 6, if(isok(n), print1(n, ", "))) } \\ Andrew Howroyd, May 04 2020

Crossrefs

Cf. A006093, A005097, A024892, A087370, A005098, A005099, A024898, A024899.

Sequence in context: A226701 A235170 A252414 * A030061 A122707 A347200

Adjacent sequences: A333718 A333719 A333720 * A333722 A333723 A333724

Keyword

nonn

Author

Pedro Caceres, May 04 2020

Status

approved