OFFSET
1,3
COMMENTS
EXAMPLE
a(3)=2 because 12+r and 6+r are both prime for only 2 values of r: 1 and 5.
MATHEMATICA
For[lst={}; n=1, n<=100, n++, cnt=0; For[k=1, k<2n, k=k+2, If[PrimeQ[4n+k]&&PrimeQ[2n+k], cnt++ ]]; AppendTo[lst, cnt]]; lst
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
T. D. Noe, May 29 2002
STATUS
approved