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A201734
Numbers n such that 90*n + 47 is prime.
19
0, 1, 2, 3, 6, 7, 9, 10, 13, 14, 16, 18, 20, 22, 24, 25, 27, 29, 31, 32, 38, 39, 43, 44, 49, 50, 51, 53, 56, 63, 64, 65, 66, 69, 77, 80, 83, 84, 87, 90, 91, 95, 98, 101, 102, 105, 106, 107, 108, 109, 111, 116, 118, 120, 121, 122, 123, 129, 132, 134, 135, 137
OFFSET
1,3
COMMENTS
A reverse reading of A142313; all entries of A142313 have digital root 2 and last digit 7.
LINKS
FORMULA
a(n) = (A142313(n)-47)/90.
MAPLE
for n from 0 to 240 do
p := 90*n+47 ;
if isprime(p) then
printf("%d, ", n) ;
end if;
end do: # R. J. Mathar, Dec 05 2011
MATHEMATICA
Select[Range[0, 400], PrimeQ[90 #+47]&] (* Vincenzo Librandi, Dec 11 2011 *)
PROG
(Magma) [n: n in [0..200] | IsPrime(90*n+47)]; // Vincenzo Librandi, Dec 11 2011
(PARI) is(n)=isprime(90*n+47) \\ Charles R Greathouse IV, Feb 17 2017
CROSSREFS
KEYWORD
nonn,easy,less
AUTHOR
J. W. Helkenberg, Dec 04 2011
STATUS
approved