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A131748
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Minimum prime that raised to the powers from 1 to n produces numbers whose sums of digits are also primes.
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0
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2, 5, 739, 47, 4229, 2803, 27617, 142589, 108271, 2347283, 1108739, 300776929, 300776929, 14674550173, 92799126239
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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EXAMPLE
| 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
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MAPLE
| 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);
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CROSSREFS
| Cf. A046704.
Sequence in context: A133378 A068105 A065588 * A176117 A078748 A051131
Adjacent sequences: A131745 A131746 A131747 * A131749 A131750 A131751
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KEYWORD
| nonn,base
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AUTHOR
| Paolo P. Lava & Giorgio Balzarotti (paoloplava(AT)gmail.com), Oct 29 2007
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EXTENSIONS
| a(12)-a(13) from Charles R Greathouse IV, Nov 18 2010
a(14)-a(15) from Charles R Greathouse IV, Mar 09, 2011
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