OFFSET
1,1
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
EXAMPLE
a(1)=2 because prime(2-1)=2 and prime(2+1)=5 are not of form 6k+1.
MATHEMATICA
f6kQ[n_]:=And@@(!IntegerQ[(#-1)/6]&/@{Prime[n-1], Prime[n+1]}); Select[ Range[2, 300], f6kQ] (* Harvey P. Dale, Feb 29 2012 *)
CROSSREFS
KEYWORD
nonn,easy,less
AUTHOR
Juri-Stepan Gerasimov, Feb 11 2010
EXTENSIONS
1 removed by Charles R Greathouse IV, Mar 25 2010
STATUS
approved