2,1

No zeros are allowed in the decimal representation of a(n).

a(5) = 14423 since 1^4423+14^423+144^23+1442^3 is prime.

(* first do *) Needs["DiscreteMath`Combinatorica`"] (* then *) f[n_] := Block[{k = (10^n - 1)/9}, While[id = IntegerDigits@k; First@ Union@ id == 0 || !PrimeQ[Plus @@ Table[FromDigits@ Take[id, {1, k}]^FromDigits@ Take[id, {k + 1, n}], {k, n - 1}]], k++ ]; k]; Do[Print[f[n]] // Timing, {n, 2, 7}] - Robert G. Wilson v (rgwv(at)rgwv.com), Apr 27 2006

Cf. A113762.

Sequence in context: A074088 A044353 A044734 this_sequence A053052 A002299 A041852

Adjacent sequences: A117385 A117386 A117387 this_sequence A117389 A117390 A117391

base,more,nonn

Ray G. Opao (1260(AT)email.com), Apr 25 2006

a(6) from Robert G. Wilson v (rgwv(at)rgwv.com) and Farideh Firoozbakht (mymontain(AT)yahoo.com), Apr 27 2006