A243301 Numbers k such that k^7 - k^6 - k^5 - k^4 - k^3 - k^2 - k - 1 is prime.

30, 38, 66, 110, 144, 156, 164, 174, 194, 210, 222, 230, 266, 278, 282, 318, 354, 374, 392, 432, 474, 528, 540, 552, 588, 630, 636, 650, 704, 714, 716, 812, 918, 960, 1076, 1086, 1122, 1142, 1190, 1224, 1322, 1362, 1388, 1394, 1418, 1452, 1506, 1508, 1532, 1538, 1596

Offset

1,1

Comments

Every term is even.

Links

Table of n, a(n) for n=1..51.

Example

30^7 - 30^6 - 30^5 - 30^4 - 30^3 - 30^2 - 30 - 1 = 21115862069 is prime. Thus 30 is a member of this sequence.

Mathematica

Select[Range[1600], PrimeQ[#^7-Total[#^Range[0, 6]]]&] (* Harvey P. Dale, Jul 04 2021 *)

Prog

(Python)
import sympy
from sympy import isprime
{print(n, end=', ') for n in range(10**3) if isprime(n**7-n**6-n**5-n**4-n**3-n**2-n-1)}
(PARI) for(n=1, 10^3, if(ispseudoprime(n^7-sum(i=0, 6, n^i)), print1(n, ", ")))

Crossrefs

Sequence in context: A298366 A130038 A325449 * A001995 A004433 A223727

Adjacent sequences: A243298 A243299 A243300 * A243302 A243303 A243304

Keyword

nonn

Author

Derek Orr, Jun 03 2014

Status

approved