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A088875 Cyclotomic(n,-n) is prime. 2
1, 3, 4, 5, 6, 9, 12, 14, 17, 82, 86, 157, 158, 180, 210, 236, 245, 368, 462, 842, 1034, 3512, 3977, 8636 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

This is a generalization of A056826. See A088817 for another generalization. Note that (n^n+1)/(n+1) = cyclotomic(n,-n) when n is prime. Also note that, for odd n>1, cyclotomic(n,-n) = cyclotomic(2n,n) and for n a multiple of 4, cyclotomic(n,-n) = cyclotomic(n,n).

Some of the larger entries may only correspond to probable primes.

LINKS

Table of n, a(n) for n=1..24.

Eric Weisstein's World of Mathematics, Cyclotomic Polynomial

MATHEMATICA

Do[p=Prime[n]; If[PrimeQ[Cyclotomic[n, -n]], Print[p]], {n, 100}]

CROSSREFS

Cf. A056826 ((n^n+1)/(n+1) is prime), A070519 (cyclotomic(n, n) is prime), A088817 (cyclotomic(2n, n) is prime).

Sequence in context: A228895 A267322 A218929 * A022884 A105857 A103055

Adjacent sequences:  A088872 A088873 A088874 * A088876 A088877 A088878

KEYWORD

hard,nonn

AUTHOR

T. D. Noe, Oct 20 2003

STATUS

approved

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Last modified January 24 01:05 EST 2020. Contains 331178 sequences. (Running on oeis4.)