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A110044
a(0) = 11, a(1) = 23; for n > 1, a(n) = |a(n-1) - a(n-2)|.
2
11, 23, 12, 11, 1, 10, 9, 1, 8, 7, 1, 6, 5, 1, 4, 3, 1, 2, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1
OFFSET
0,1
COMMENTS
Since a(18)=a(19)=1, starting from here the sequence is periodic with period 3: 1,1,0,1,1,0,1,1,0,... - Emeric Deutsch, Jul 13 2005
FORMULA
a(n) = 2/3 + 1/3*cos(2*Pi*n/3) + 1/3*3^(1/2)*sin(2*Pi*n/3) for n >= 19. - Richard Choulet, Dec 12 2008
MAPLE
a[0]:=11: a[1]:=23: for n from 2 to 120 do a[n]:=abs(a[n-1]-a[n-2]) od: seq(a[n], n=0..120); # Emeric Deutsch, Jul 13 2005
MATHEMATICA
Join[{11, 23, 12, 11, 1, 10, 9, 1, 8, 7, 1, 6, 5, 1, 4, 3, 1, 2}, LinearRecurrence[{0, 0, 1}, {1, 1, 0}, 85]] (* Ray Chandler, Aug 25 2015 *)
CROSSREFS
Cf. A141571.
Sequence in context: A253684 A364165 A180481 * A032663 A352868 A119815
KEYWORD
nonn,easy
AUTHOR
Edwin F. Sampang, Jul 09 2005
EXTENSIONS
More terms from Emeric Deutsch, Jul 13 2005
STATUS
approved