A237190 Numbers k such that k+1, 2k+1, 3k+1, 4k+1, 5k+1 are five primes.

10830, 25410, 26040, 88740, 165900, 196560, 211050, 224400, 230280, 247710, 268500, 268920, 375480, 377490, 420330, 451410, 494340, 512820, 592620, 604170, 735750, 751290, 765780, 799170, 808080, 952680, 975660, 1053690, 1064190, 1132860, 1156170, 1532370, 1559580

Offset: 1

Author

Alex Ratushnyak, Feb 04 2014

Keywords

• nonn

Comments

A subsequence of A237189.

All terms are divisible by 30, and b(n) = a(n)/30 begins: 361, 847, 868, 2958, 5530, 6552, 7035, 7480, 7676, 8257, 8950, 8964, 12516, 12583, 14011, ...

Links

• Giovanni Resta, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A088250, A064238, A124410, A237189.

Programs

Mathematica

Select[30*Range[52000],AllTrue[#*Range[5]+1,PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Dec 31 2017 *)

Python

from sympy import isprime
for n in range(2000000):
    if isprime(n+1) and isprime(2*n+1) and isprime(3*n+1) and isprime(4*n+1) and isprime(5*n+1):
        print(n, end=', ')