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A165326
a(0)=a(1)=1, a(n) = -a(n-1) for n > 1.
9
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, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, 1
OFFSET
0,1
COMMENTS
Inverse binomial transform of A040000(n) = 1,2,2,2,2,...; binomial transform of (-1)^(n+1)*A000918(n) = 1,0,-2,6,-14,30,-62,... - Philippe Deléham, Sep 16 2009
This is also the Z-sequence of the Riordan triangle A105809. See the W. Lang link under A006232 for Riordan A- and Z-sequences. - Wolfdieter Lang, Oct 04 2014
FORMULA
G.f.: (1+2*x)/(1+x).
E.g.f.: 2-exp(-x).
a(n) = -a(n-1). - Wesley Ivan Hurt, Apr 23 2021
MATHEMATICA
PadRight[{1}, 120, {-1, 1}] (* Harvey P. Dale, Dec 04 2012 *)
Join[{1}, LinearRecurrence[{-1}, {1}, 83]] (* Ray Chandler, Aug 12 2015 *)
CROSSREFS
Cf. A033999.
Sequence in context: A174351 A339265 A181432 * A143621 A292117 A098417
KEYWORD
easy,sign,mult
AUTHOR
Philippe Deléham, Sep 14 2009
STATUS
approved