A110705 Numbers n such that "n 42's followed by 43" is prime.
0, 1, 2, 3, 4, 7, 17, 24, 59, 199, 743, 2558, 4896, 5539, 6192, 10977, 27679
Offset: 1
Programs
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Mathematica
t = 1; Do[ t = t*100 - 57; If[PrimeQ[t], Print[n]], {n, 0, 3000}] robinsonQ[n_] := PrimeQ[(100^(1 + n) - 1) * 42/99 + 1]; Select[Range[200], robinsonQ] (* Robert G. Wilson v, Jan 23 2015 *) -
PARI
t=1; for(n=0,10^6,t=100*t-57;if(ispseudoprime(t),print1(n,", "))); \\ Joerg Arndt, Nov 21 2014
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PFGW
ABC2 1+(100^(1+$a)-1)*42/99 a: from 0 to 28000 \\ Charles R Greathouse IV, Mohsen Hozan, Jan 23 2015
Extensions
a(13)-a(17) from Mohsen Hozan, Feb 10 2015
Comments