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A119558 a(1)=0,a(2)=0,a(3)=1 then a(n)=abs(a(n-1)-a(n-2))+(-1)^n*a(n-3). 1
0, 0, 1, 1, 0, 2, 1, 1, -2, 4, 5, -1, 2, 8, 7, 3, -4, 14, 15, -3, 4, 22, 21, 5, -6, 32, 33, -5, 6, 44, 43, 7, -8, 58, 59, -7, 8, 74, 73, 9, -10, 92, 93, -9, 10, 112, 111, 11, -12, 134, 135, -11, 12, 158, 157, 13, -14, 184, 185, -13, 14, 212, 211, 15, -16, 242, 243, -15, 16, 274, 273, 17, -18, 308, 309, -17, 18, 344 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,6

COMMENTS

See A104156 for an order 2 example.

REFERENCES

B. Cloitre, On strange predictible recursions, preprint 2006

LINKS

Table of n, a(n) for n=0..77.

FORMULA

for n>=1 a(4n)=(-1)^n*(2*floor(n/2)-1), a(4*n+1)=(-1)^(n+1)*2*floor(n/2), a(4*n+2)=n^2-n+2, a(4*n+3)=n^2-n+2+(-1)^n

CROSSREFS

Sequence in context: A253473 A026120 A108746 * A210112 A024735 A024957

Adjacent sequences:  A119555 A119556 A119557 * A119559 A119560 A119561

KEYWORD

sign

AUTHOR

Benoit Cloitre, May 30 2006

STATUS

approved

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Last modified August 21 13:36 EDT 2017. Contains 290890 sequences.