OFFSET
1,1
COMMENTS
Except for the first pair of primes and for twin primes there is always at least one number of the form 6n+3 between two successive primes.
EXAMPLE
a(3)=0 because between prime(3) and prime(4) there are no numbers of the form 6k+3;
a(4)=1 because between prime(4) and prime(5) there is one number of the form 6k+3: 9.
MATHEMATICA
f[n_] := Count[Table[Mod[k, 6], {k, Prime[n], Prime[n + 1]}], 3]; Table[If[f[n] == 0, 0, 1], {n, 120}] (* Ray Chandler, Oct 17 2006 *)
Join[{1, 1}, If[Last[#]-First[#]==2, 0, 1]&/@Partition[Prime[Range[ 3, 200]], 2, 1]] (* Harvey P. Dale, Nov 27 2013 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Giovanni Teofilatto, May 02 2005
EXTENSIONS
Edited by Ray Chandler, Oct 17 2006
STATUS
approved