OFFSET
1,1
COMMENTS
2^2+2^2=8, 2^3+3^2=17, 3^3+3^3=54, 2^5+5^2=57, 2^7+7^2=177, 3^5+5^3=368,..
MATHEMATICA
nMax=10^12; lim=PrimePi[Log[2, nMax]]; f[a_, b_]:=Prime[a]^Prime[b] + Prime[b]^Prime[a]; Select[Union[Flatten[Table[f[a, b], {a, lim}, {b, lim}]]], #<=nMax&]
nMax=10^12; lim=PrimePi[Log[2, nMax]]; Select[Union[First[#]^Last[#] + Last[#]^First[#]&/@ Tuples[Prime[Range[lim]], {2}]], #<=nMax&] (* Harvey P. Dale, Mar 12 2011 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Joseph Stephan Orlovsky, Feb 08 2010
STATUS
approved