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A180488
Partial sums of A006864.
0
0, 1, 3, 9, 23, 60, 152, 388, 984, 2501, 6347, 16117, 40911, 103864, 263664, 669352, 1699216, 4313673, 10950739, 27799745, 70572839, 179157364, 454811656, 1154592108, 2931065640, 7440849549, 18889457819, 47953075565
OFFSET
1,3
FORMULA
a(n) = +3*a(n-1) -4*a(n-3) +3*a(n-4) -a(n-5). G.f.: x^2 / ( (x-1)*(x^4-2*x^3+2*x^2+2*x-1) ). [R. J. Mathar, Sep 19 2010]
CROSSREFS
Cf. A006864.
Sequence in context: A146818 A309301 A323798 * A318860 A318818 A026599
KEYWORD
nonn,easy
AUTHOR
Jonathan Vos Post, Sep 07 2010
EXTENSIONS
Edited (changed definition, deleted incorrect terms) by N. J. A. Sloane, Sep 09 2010
STATUS
approved