A046887 - OEIS

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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.

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

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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-François 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