OFFSET
1,1
COMMENTS
In some sense this is the opposite to the problem of (consecutive) primes in the arithmetic progression PAP or CPAP.
Note that in many cases p + 6*k are composite for k = 1..m with m > 100.
Maximal found value of m = 148 for a(615) = 50100585793 = prime(2123734960).
Is it possible to find primes p giving, say, thousand composites p+6*k, k = 1..1000 or even more?
Of course we exclude the cases p = 2 and 3 as they give an infinite number of composites of the form p + 6*k.
LINKS
Zak Seidov, Table of n, a(n) for n = 1..2035 (all terms up to 10^11)
EXAMPLE
1917214927 + {6, 12, 18, 24, ..., 600} are all composite.
MATHEMATICA
Select[Prime[Range[3*10^8]], AllTrue[#+6*Range[100], CompositeQ]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Mar 25 2018 *)
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Zak Seidov, Dec 03 2013
EXTENSIONS
First two terms prepended by Harvey P. Dale, Mar 25 2018
2, 3 removed again by Georg Fischer, Jan 20 2019
STATUS
approved