A156204 First primes of an arithmetic progression of six primes with common difference 30.

7, 107, 359, 541, 2221, 6673, 7457, 10103, 25643, 26861, 27337, 35051, 56149, 61553, 65557, 73523, 84317, 110819, 115733, 131581, 135151, 137447, 179321, 228587, 243553, 252163, 279421, 281717, 310711, 320119, 337367, 345487, 347167, 357079

Offset: 1

Author

Ki Punches, Feb 05 2009

Keywords

• nonn

Comments

Subsequence of A155760. - R. J. Mathar, Feb 07 2009

After the first term, all terms are congruent to 9 (mod 14). Gaps of 14 occur at a(n) = 22037759, 400852853, ... - Zak Seidov, Aug 01 2013

Subsequence of A227281. - Zak Seidov, Aug 26 2014

Note that a(n)+6*30 is composite for all n: a(1)+180 is divisible by 11 and for n>1 a(n)+180 is divisible by 7. - Zak Seidov, Apr 11 2015

Links

• Michael B. Porter, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A155760, A227281.

Programs

Magma

[p: p in PrimesUpTo(360000)| IsPrime(p+30) and IsPrime(p+60) and IsPrime(p+90)and IsPrime(p+120)and IsPrime(p+150)]; // Vincenzo Librandi, Apr 13 2015

Maple

for n from 1 to 60000 do p := ithprime(n) ; if isprime(p+30) and isprime(p+60) and isprime(p+90) and isprime(p+120) and isprime(p+150) then printf("%d,",p) ; fi; od: # R. J. Mathar, Feb 07 2009

Mathematica

Select[Range[360000], PrimeQ[#] && PrimeQ[# + 30] && PrimeQ[# + 60] && PrimeQ[# + 90] && PrimeQ[# + 120] && PrimeQ[# + 150] &] (* Vincenzo Librandi, Apr 13 2015 *)

PARI

is_A156204(n) = isprime(n) && isprime(n+30) && isprime(n+60) && isprime(n+90) && isprime(n+120) && isprime(n+150) \\ Michael B. Porter, Aug 01 2013

Extensions

Corrected and extended by R. J. Mathar and Ray Chandler, Feb 08 2009