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A124751 Expansion of (1+x^2+x^4)/(1-x^6+x^7). 1
1, 0, 1, 0, 1, 0, 1, -1, 1, -1, 1, -1, 1, -2, 2, -2, 2, -2, 2, -3, 4, -4, 4, -4, 4, -5, 7, -8, 8, -8, 8, -9, 12, -15, 16, -16, 16, -17, 21, -27, 31, -32, 32, -33, 38, -48, 58, -63, 64, -65, 71, -86, 106, -121, 127, -129, 136, -157, 192, -227, 248 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,14

COMMENTS

Diagonal sums of number triangle A124749.

LINKS

Table of n, a(n) for n=0..60.

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

FORMULA

a(n)=sum{k=0..floor(n/2), C(floor(k/3),n-2k)*(-1)^n}

MATHEMATICA

CoefficientList[Series[(1+x^2+x^4)/(1-x^6+x^7), {x, 0, 100}], x] (* or *) LinearRecurrence[{0, 0, 0, 0, 0, 1, -1}, {1, 0, 1, 0, 1, 0, 1}, 100] (* Harvey P. Dale, Mar 10 2017 *)

CROSSREFS

Sequence in context: A317245 A332277 A109701 * A103374 A208251 A241087

Adjacent sequences:  A124748 A124749 A124750 * A124752 A124753 A124754

KEYWORD

easy,sign

AUTHOR

Paul Barry, Nov 06 2006

STATUS

approved

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Last modified November 30 21:20 EST 2021. Contains 349426 sequences. (Running on oeis4.)