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A132342
a(n) = (a(n-1)*a(n-4)) - (a(n-2)*a(n-3)), with a(1)=a(2)=a(3)=a(4)=1.
0
1, 1, 1, 1, 0, -1, -1, -1, -1, 0, -1, 1, -1, 1, 0, 1, -1, -1, 1, 0, 1, -1, -1, 1, 0, 1, -1, -1, 1, 0, 1, -1, -1, 1, 0, 1, -1, -1, 1, 0, 1, -1, -1, 1, 0, 1, -1, -1, 1, 0, 1, -1, -1, 1, 0, 1, -1, -1, 1, 0, 1, -1, -1, 1, 0, 1, -1, -1, 1, 0, 1, -1, -1, 1, 0, 1, -1, -1, 1, 0, 1, -1, -1, 1, 0, 1, -1, -1, 1, 0, 1, -1, -1, 1, 0, 1, -1, -1, 1, 0, 1, -1, -1, 1, 0
OFFSET
1,1
COMMENTS
Becomes cyclic with period 5: {-1, 1, 0, 1, -1} at a(13). - Stefan Steinerberger, Nov 17 2007
MATHEMATICA
a[1] = a[2] = a[3] = a[4] = 1; a[n_] := a[n] = a[n - 1]*a[n - 4] - a[n - 2]*a[n - 3]; Array[a, 105] (* Robert G. Wilson v, Nov 09 2007 *)
a = {1, 1, 1, 1}; Do[AppendTo[a, a[[ -1]]*a[[ -4]] - a[[ -2]]*a[[ -3]]], {90}]; a (* Stefan Steinerberger, Nov 17 2007 *)
CROSSREFS
Sequence in context: A120529 A292301 A099443 * A156174 A358847 A187967
KEYWORD
sign,easy
AUTHOR
Ben Branman, Nov 08 2007
EXTENSIONS
More terms from Robert G. Wilson v, Nov 09 2007
STATUS
approved