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A152832
a(0) = -2; a(n) = n - a(n-1) for n > 0.
13
-2, 3, -1, 4, 0, 5, 1, 6, 2, 7, 3, 8, 4, 9, 5, 10, 6, 11, 7, 12, 8, 13, 9, 14, 10, 15, 11, 16, 12, 17, 13, 18, 14, 19, 15, 20, 16, 21, 17, 22, 18, 23, 19, 24, 20, 25, 21, 26, 22, 27, 23, 28, 24, 29, 25, 30, 26, 31, 27, 32, 28, 33, 29, 34, 30, 35, 31, 36, 32, 37, 33, 38, 34, 39, 35
OFFSET
0,1
FORMULA
From R. J. Mathar, Jan 03 2009, Aug 14 2009: (Start)
a(n) = (n+1)/2-(9*(-1)^n+1)/4.
G.f.: -(2*x-1)*(x-2)/((1+x)*(x-1)^2).
a(n) = a(n-1)+a(n-2)-a(n-3). (End)
MATHEMATICA
lst={}; a=2; Do[a=n-a; AppendTo[lst, a], {n, 0, 6!}]; lst
RecurrenceTable[{a[0]==-2, a[n]==n-a[n-1]}, a, {n, 80}] (* or *) With[ {nn=40}, Riffle[ Range[-2, nn-2], Range[3, nn+3]]] (* Harvey P. Dale, Jun 02 2019 *)
CROSSREFS
Sequence in context: A127412 A304791 A306646 * A211343 A039661 A293668
KEYWORD
sign,easy
AUTHOR
EXTENSIONS
Definition corrected by N. J. A. Sloane, Jan 11 2009
Formula adapted to offset by R. J. Mathar, Aug 14 2009
STATUS
approved