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A117318 Numbers n such that Phi(n,x) is a flat cyclotomic polynomial of order four. 7
431985, 757335, 865365, 1134915, 1296885, 1297815, 1675365, 1729335, 1891815, 2161785, 2162715, 2595165, 2648715, 2649585, 3027165, 3028035, 3132015, 3133785, 3347985, 3405615, 3565785, 3784065, 3891585, 4698465, 4920285, 5188935, 5189865, 5676315 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

A flat polynomial is defined to be a polynomial whose coefficients are -1, 0, or 1. Order four means that n is the product of four odd primes p<q<r<s.

For pqrs to be flat, it appears that three conditions on p < q < r < s are required: q = -1 (mod p), r = +-1 (mod pq), and s = +-1 (mod pqr). [T. D. Noe, Apr 13 2010]

LINKS

T. D. Noe, Table of n, a(n) for n=1..216

Nathan Kaplan, Flat cyclotomic polynomials of order four and higher, #A30, Integers 10 (2010), 357-363.

CROSSREFS

Cf. A117223 (third-order flat cyclotomic polynomials).

Sequence in context: A233620 A271110 A237926 * A085092 A117151 A186048

Adjacent sequences:  A117315 A117316 A117317 * A117319 A117320 A117321

KEYWORD

nonn

AUTHOR

T. D. Noe, Mar 07 2006

STATUS

approved

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Last modified June 22 19:11 EDT 2021. Contains 345388 sequences. (Running on oeis4.)