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A112469 Partial sums of (-1)^n*F(n-1). 3
1, 1, 2, 1, 3, 0, 5, -3, 10, -11, 23, -32, 57, -87, 146, -231, 379, -608, 989, -1595, 2586, -4179, 6767, -10944, 17713, -28655, 46370, -75023, 121395, -196416, 317813, -514227, 832042, -1346267, 2178311, -3524576, 5702889, -9227463, 14930354, -24157815, 39088171, -63245984, 102334157 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

Diagonal sums of Riordan array (1/(1-x), x/(1+x)), A112468.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..300

Index entries for linear recurrences with constant coefficients, signature (0,2,-1).

FORMULA

G.f.: (1+x)/((1-x)(1+x-x^2));

a(n) = Sum_{k=0..floor(n/2)} Sum_{j=0..n-2k} C(n-k-j-1, n-2k-j)*(-1)^(n-j).

MAPLE

a[0]:=1:a[1]:=1:a[2]:=2:a[3]:=1:for n from 4 to 50 do a[n]:=2*a[n-2]-a[n-3] od: seq(a[n], n=0..42); # Zerinvary Lajos, Apr 04 2008

MATHEMATICA

Accumulate[Table[(-1)^n Fibonacci[n-1], {n, 0, 50}]] (* Harvey P. Dale, Nov 05 2011 *)

CROSSREFS

Cf. A078024.

Sequence in context: A281617 A280544 A078024 * A330502 A249455 A248967

Adjacent sequences:  A112466 A112467 A112468 * A112470 A112471 A112472

KEYWORD

easy,sign

AUTHOR

Paul Barry, Sep 06 2005

STATUS

approved

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Last modified March 3 12:16 EST 2021. Contains 341762 sequences. (Running on oeis4.)