A239346 -id:A239346 - cp's OEIS frontend

A239417 Numbers n such that n^9-9 is prime.

2, 62, 86, 88, 116, 152, 266, 292, 310, 326, 338, 356, 406, 436, 466, 470, 518, 550, 568, 616, 626, 650, 688, 700, 722, 812, 850, 926, 956, 992, 1058, 1076, 1126, 1186, 1252, 1430, 1550, 1570, 1642, 1672, 1682, 1766, 1808, 1852, 1868, 1888, 2138, 2210, 2306

Offset: 1

Derek Orr, Mar 17 2014

nonn

Note that all numbers in this sequence are even.

			2^9-9 = 503 is prime. Thus, 2 is a member of this sequence.

Cf. A028870, A153974, A239413, A239414, A239415, A239416, A239418, A239346.

is(n)=isprime(n^9-9) \\ Charles R Greathouse IV, Feb 20 2017

import sympy
from sympy import isprime
{print(n) for n in range(10**4) if isprime(n**9-9)}

A239505 Numbers n such that n^9+9 and n^9-9 are prime.

Original entry on oeis.org

2, 1642, 2870, 2948, 4238, 5480, 5920, 7502, 8210, 8248, 9328, 11572, 13538, 13610, 14818, 14908, 19298, 21022, 21890, 21988, 22340, 23000, 23252, 26282, 26380, 29168, 31660, 32602, 33338, 33650, 36220, 38248, 38422, 43490, 43910, 44948, 45188, 46048

Offset: 1

Derek Orr, Mar 20 2014

nonn

All numbers in this sequence are even.

Intersection of A239346 and A239417.

			2^9+9 = 521 is prime and 2^9-9 = 503 is prime. Thus, 2 is a member of this sequence.

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

Cf. A239346, A239417.

Select[Range[50000],AllTrue[#^9+{9,-9},PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Feb 12 2015 *)

import sympy
from sympy import isprime
def TwoBoth(x):
  for k in range(10**6):
    if isprime(k**x+x) and isprime(k**x-x):
      print(k)
TwoBoth(9)

cp's OEIS Frontend

A239417 Numbers n such that n^9-9 is prime.

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