OFFSET
0,5
COMMENTS
It appears that a(n)=0 for n=0,5,14,24 only. See A129634 for the least k.
LINKS
T. D. Noe, Table of n, a(n) for n = 0..10000
EXAMPLE
a(4)=2 because 10+1 and 10+3 are prime; a(7)=3 because 28+1, 28+3 and 28+15 are primes.
MATHEMATICA
nn=100; tri=Range[0, nn]Range[nn+1]/2; Table[cnt=0; Do[If[PrimeQ[tri[[k]]+tri[[n]]], cnt++ ], {k, n}]; cnt, {n, Length[tri]}]
CROSSREFS
KEYWORD
nonn
AUTHOR
T. D. Noe, Jun 04 2007
STATUS
approved