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A046887 Numbers n such that the cyclotomic polynomial of order n has a nonzero coefficient which does not appear in any cyclotomic polynomials of lower order. 5
1, 105, 165, 385, 595, 1365, 1785, 2145, 2805, 3135, 6545, 7917, 10465, 11305, 15015, 17255, 20615, 25935, 26565, 40755, 106743, 171717, 255255, 279565, 285285, 327845, 350455, 373065, 463505 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..29.

EXAMPLE

The cyclotomic polynomial cycl(105) is the first one to contain a nonzero coefficient which is not 1 or -1: it contains -2. Then for j=165 the coefficient 2 appears, etc.

MAPLE

with(numtheory): me := {}: for j from 1 to 10000 do h := {coeffs(cyclotomic(j, x))}: if me union h <> me then print(j, h minus me); me := me union h; fi; od:

MATHEMATICA

coes = {}; Reap[For[j = 1, j <= 10000, j++, h = Select[ CoefficientList[ Cyclotomic[j, x], x], # != 0 &]; u = Union[coes, h]; If[u != coes, Print[j]; Sow[j]; coes = u]]][[2, 1]] (* Jean-Fran├žois Alcover, Nov 19 2012, after Maple *)

CROSSREFS

Cf. A013594.

Sequence in context: A234103 A128284 A161962 * A026066 A167629 A326141

Adjacent sequences:  A046884 A046885 A046886 * A046888 A046889 A046890

KEYWORD

nonn,nice

AUTHOR

Christoph Lamm (lamm(AT)math.uni-bonn.de)

EXTENSIONS

a(13)-a(19) from Giovanni Resta, Feb 01 2006

Added 10 terms - T. D. Noe, Dec 10 2008

STATUS

approved

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Last modified April 6 11:51 EDT 2020. Contains 333273 sequences. (Running on oeis4.)