OFFSET
2,1
COMMENTS
See A113833 for the case of all subset averages being distinct primes. The Mathematica program is for row 4.
LINKS
Andrew Granville, Prime number patterns
EXAMPLE
The set of primes generated by {5, 17, 29} is {5, 11, 17, 17, 17, 23, 29}.
Triangle begins:
3, 7
5, 17, 29
5, 509, 1013, 1109
MATHEMATICA
Needs["DiscreteMath`Combinatorica`"]; nn=PrimePi[1277]; Do[s=Prime[{l, k, j, i}]; ss=Rest[Subsets[s]]; ave=(Plus@@@ss)/(Length/@ss); If[And@@(IntegerQ/@ave) && And@@PrimeQ[ave], Break[]], {l, 2, nn}, {k, 2, l-1}, {j, 2, k-1}, {i, 2, j-1}]; Reverse[s]
CROSSREFS
KEYWORD
nonn,tabf,hard,more
AUTHOR
T. D. Noe, Jan 30 2006
STATUS
approved