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Primes of form x^y + y^x + 1
0

%I #1 Jun 01 2010 03:00:00

%S 3,5,7,11,13,17,19,23,29,31,37,41,43,47,101,2531,4241,5393,94933,

%T 262469,16797953,48989177,78371693633,2552470327703,4747732369319,

%U 17832200896513,131621703955647041,4052555153019035587

%N Primes of form x^y + y^x + 1

%e a(1)=1^1+1^1+1=3 a(2)=1^3+3^1+1=5 a(3)=1^5+5^1+1=7 ... a(15)=2^6+6^2+1=101

%t a[n_] := Block[{}, For[l = {}; i = 1, i < n, i++, For[j = i, j < n, j++, x = i^j + j^i + 1; If[PrimeQ[x], l = Append[l, x]]]]; Print[Sort[Union[l]]]]; a[50]

%Y Cf. A094133, A172142

%K nonn

%O 1,1

%A Cheng Zhang (cz1(AT)rice.edu), Jan 26 2010, Mar 03 2010