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A086369 Number of factors over Q in the factorization of T_n(x) - 1 where T_n(x) is the Chebyshev polynomial of the first kind. 2
1, 2, 3, 4, 3, 6, 3, 6, 5, 6, 3, 10, 3, 6, 7, 8, 3, 10, 3, 10, 7, 6, 3, 14, 5, 6, 7, 10, 3, 14, 3, 10, 7, 6, 7, 16, 3, 6, 7, 14, 3, 14, 3, 10, 11, 6, 3, 18, 5, 10, 7, 10, 3, 14, 7, 14, 7, 6, 3, 22, 3, 6, 11, 12, 7, 14, 3, 10, 7, 14, 3, 22, 3, 6, 11, 10, 7, 14, 3, 18 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

If p is an odd prime then a(p) = 3.

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..2049

PROG

(PARI) a(n)={vecsum(factor(polchebyshev(n, 1, x)-1)[, 2])} \\ Andrew Howroyd, Jul 10 2018

CROSSREFS

Cf. A086374.

Sequence in context: A290139 A317588 A080383 * A337532 A092089 A117659

Adjacent sequences:  A086366 A086367 A086368 * A086370 A086371 A086372

KEYWORD

nonn

AUTHOR

Yuval Dekel (dekelyuval(AT)hotmail.com), Sep 08 2003

EXTENSIONS

a(14) corrected and a(21)-a(80) added by Andrew Howroyd, Jul 10 2018

STATUS

approved

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Last modified October 23 04:06 EDT 2021. Contains 348211 sequences. (Running on oeis4.)