OFFSET
1,2
COMMENTS
A060461 is the main sequence for this entry.
Numbers k such that 6*k-1 and 6*k+1 are twin nonprimes.
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
FORMULA
a(n+1) = A060461(n).
a(n) = n + O(n/log n). - Charles R Greathouse IV, Feb 17 2017
MAPLE
isA171696 := proc(n) not isprime(6*n+1) and not isprime(6*n-1) ; end proc: for n from 0 to 300 do if isA171696(n) then printf("%d, ", n) ; end if; end do: # R. J. Mathar, Mar 18 2010
MATHEMATICA
Select[Range[0, 225], !Or @@ PrimeQ[6# + {-1, 1}] &] (* Amiram Eldar, Jan 21 2020 *)
PROG
(PARI) is(n)=!isprime(6*n-1) && !isprime(6*n+1) \\ Charles R Greathouse IV, Feb 17 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Juri-Stepan Gerasimov, Dec 15 2009
STATUS
approved