1,1

The sequence appears to be finite with 11 as maximum power.

n=3 -> 739:

739^1 = 739 Sum_digits(739) = 19 which is prime;

739^2 = 546121 Sum_digits(546121) = 19 which is prime;

739^3 = 403583419 Sum_digits(403583419) = 37 which is prime;

n=5 -> p=4229:

4229^1 = 4229 Sum_digits(4229) = 17 which is prime;

4229^2 = 17884441 Sum_digits(17884441) = 37 which is prime

4229^3 = 75633300989 Sum_digits(75633300989) = 53 which is prime

4229^4 = 319853229882481 Sum_digits(319853229882481) = 73 which is prime

4229^5 = 1352659309173012149 Sum_digits(1352659309173012149) = 71 which is prime

P:=proc(n, m) local cont, i, k, w, ok; ok:=true; i:=0; while ok do i:=i+1; cont:=0; w:=i; if isprime(i) then while cont<50 and isprime(w) do cont:=cont+1; w:=0; k:=i^cont; while k>0 do w:=w+k-(trunc(k/10)*10); k:=trunc(k/10); od; od; if (cont-1)=m then lprint(i, cont-1); ok:=false; fi; fi; od; end: P(10000000, 11);

Cf. A046704.

Sequence in context: A133378 A068105 A065588 this_sequence A078748 A051131 A119748

Adjacent sequences: A131745 A131746 A131747 this_sequence A131749 A131750 A131751

fini,nonn

Paolo P. Lava & Giorgio Balzarotti (ppl(AT)spl.at), Oct 29 2007