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A186039 a(n) = (-1)^A186038(n). 3
1, 1, -1, 1, 1, -1, -1, -1, -1, 1, 1, -1, 1, 1, -1, 1, 1, 1, -1, -1, 1, -1, -1, 1, 1, 1, -1, 1, 1, -1, 1, 1, -1, -1, -1, -1, 1, 1, -1, 1, 1, -1, -1, -1, 1, 1, 1, -1, 1, 1, -1, -1, -1, 1, -1, -1, 1, -1, -1, 1, 1, 1, 1, -1, -1, 1, -1, -1, 1, -1, -1 (list; graph; refs; listen; history; text; internal format)
OFFSET

0

COMMENTS

Hankel transform is A186040.

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..1000

FORMULA

a(n) = (-1)^log_3(A002426(n)/numerator(A002426(n)/3^n)).

MATHEMATICA

Join[{1}, Table[(-1)^(Log[3, GegenbauerC[n, -n, -1/2]/ (Numerator[ GegenbauerC[n, -n, -1/2]/3^n])]), {n, 1, 50}]] (* G. C. Greubel, Mar 06 2017 *)

CROSSREFS

Cf. A002426, A186038, A186040.

Sequence in context: A131554 A153881 A160357 * A057077 A262725 A070748

Adjacent sequences:  A186036 A186037 A186038 * A186040 A186041 A186042

KEYWORD

sign,easy

AUTHOR

Paul Barry, Feb 11 2011

STATUS

approved

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Last modified January 21 11:07 EST 2020. Contains 331105 sequences. (Running on oeis4.)