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A005122 Numbers n such that 8n - 1 is prime. 12
1, 3, 4, 6, 9, 10, 13, 16, 19, 21, 24, 25, 28, 30, 33, 34, 39, 45, 46, 48, 54, 55, 58, 60, 61, 63, 75, 76, 79, 81, 90, 91, 93, 94, 103, 105, 108, 111, 114, 115, 121, 123, 124, 129, 130, 133, 136, 138, 144, 153, 154, 160, 163, 165, 166, 171, 175, 178, 180 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Solutions of the equation (8*n-1)'=1, where n' is the arithmetic derivative of n. - Paolo P. Lava, Jan 03 2013

Corresponding primes are listed in A007522. - Altug Alkan, Dec 10 2015

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

MAPLE

A005122:=n->`if`(isprime(8*n-1), n, NULL): seq(A005122(n), n=1..300); # Wesley Ivan Hurt, Dec 11 2015

MATHEMATICA

a={}; Do[x=8*n-1; If[PrimeQ[x], AppendTo[a, n]], {n, 10^2}]; a (* Vladimir Joseph Stephan Orlovsky, Apr 29 2008 *)

Select[Range[160], PrimeQ[8#-1]&] (* Harvey P. Dale, Nov 25 2011 *)

PROG

(PARI) isok(n) = isprime(8*n-1); \\ Michel Marcus, Dec 10 2015

(PARI) lista(nn) = my(p, s, x, z); forprime(p = 3, nn, s = []; for(x = 0, p-1, if(x^4%p == 2%p, s = concat(s, [x]))); z = matsize(s)[2]; if(z == 2, print1((p+1)/8, ", "))) \\ Altug Alkan, Dec 10 2015

(MAGMA) [n: n in [1..200] | IsPrime(8*n-1)]; // Vincenzo Librandi, Dec 10 2015

CROSSREFS

Cf. A007522.

Sequence in context: A089986 A101448 A299231 * A166161 A130904 A034706

Adjacent sequences:  A005119 A005120 A005121 * A005123 A005124 A005125

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified April 6 16:14 EDT 2020. Contains 333276 sequences. (Running on oeis4.)