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.

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

Links

Table of n, a(n) for n=1..105.

Index entries for linear recurrences with constant coefficients, signature (-1, -1, -1, -1).

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

Adjacent sequences: A132339 A132340 A132341 * A132343 A132344 A132345

Keyword

sign,easy

Author

Ben Branman, Nov 08 2007

Extensions

More terms from Robert G. Wilson v, Nov 09 2007

Status

approved