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 A244378 Numbers k such that 1 + k + k^3 + k^5 + k^7 + k^9 + ... + k^17 is prime. 2

%I

%S 2,12,34,50,72,104,172,180,198,202,240,252,254,272,300,338,348,374,

%T 494,498,504,578,640,648,652,702,728,804,832,848,892,950,1002,1040,

%U 1060,1070,1134,1158,1184,1364,1378,1464,1564,1598,1608,1624,1630,1678,1688,1704,1734

%N Numbers k such that 1 + k + k^3 + k^5 + k^7 + k^9 + ... + k^17 is prime.

%H Vincenzo Librandi, <a href="/A244378/b244378.txt">Table of n, a(n) for n = 1..1000</a>

%t Select[Range[7000], PrimeQ[Total[#^Range[1, 17, 2]] + 1] &]

%o (Magma) [n: n in [0..2500] | IsPrime(s) where s is 1+&+[n^i: i in [1..17 by 2]]];

%o (PARI) isok(n) = isprime(1 + n + n^3 + n^5 + n^7 + n^9 + n^11 + n^13 + n^15 + n^17); \\ _Michel Marcus_, Jun 27 2014

%o (Sage)

%o i,n = var('i,n')

%o [n for n in (1..2000) if is_prime(1+(n^(2*i+1)).sum(i,0,8))] # _Bruno Berselli_, Jun 27 2014

%Y Cf. similar sequences listed in A244376.

%K nonn,easy

%O 1,1

%A _Vincenzo Librandi_, Jun 27 2014

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Last modified March 26 10:45 EDT 2023. Contains 361540 sequences. (Running on oeis4.)