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A124205 Numbers n such that 1 + n + n^3 + n^5 + n^7 + n^9 + n^11 + ... + n^45 + n^47 is prime. 5
12, 18, 39, 75, 82, 92, 133, 152, 273, 428, 568, 617, 749, 922, 949, 975, 1020, 1033, 1058, 1088, 1113, 1207, 1253, 1329, 1372, 1389, 1762, 1784, 1882, 1943, 1950, 1962, 1969, 2372, 2445, 2508, 2594, 2768, 2973, 2977, 3237, 3327, 3338, 3459, 3545, 3550, 3554 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..362

MAPLE

a:= proc(n) option remember; local k;

      for k from 1+`if`(n=1, 1, a(n-1)) while

        not isprime(1+(k^49-k)/(k^2-1)) do od; k

    end:

seq(a(n), n=1..40);  # Alois P. Heinz, Jun 26 2014

MATHEMATICA

Do[If[PrimeQ[1 + n + n^3 + n^5 + n^7 + n^9 + n^11 + n^13 + n^15 + n^17 + n^19 + n^21 + n^23 + n^25 + n^27 + n^29 + n^31 + n^33 + n^35 + n^37 + n^39 + n^41 + n^43 + n^45 + n^47], Print[n]], {n, 1, 2400}] (* Artur Jasinski *)

Select[Range[2500], PrimeQ[Total[#^Range[1, 47, 2]] + 1] &] (* Harvey P. Dale, Jan 13 2011 *)

PROG

(PARI) for(n=1, 10^4, if(ispseudoprime(sum(i=0, 23, n^(2*i+1))+1), print1(n, ", "))) \\ Derek Orr, Jun 24 2014

(MAGMA) [n: n in [0..4000] | IsPrime(s) where s is 1+&+[n^i: i in [1..47 by 2]]]; // Vincenzo Librandi, Jun 27 2014, after Derek Orr

CROSSREFS

Cf. A049407.

Sequence in context: A162694 A230354 A197464 * A133403 A152615 A258088

Adjacent sequences:  A124202 A124203 A124204 * A124206 A124207 A124208

KEYWORD

nonn

AUTHOR

Artur Jasinski, Dec 13 2006

EXTENSIONS

a(35) and beyond from Derek Orr, Jun 24 2014

STATUS

approved

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Last modified July 20 22:20 EDT 2019. Contains 325189 sequences. (Running on oeis4.)