A140345 a(n)=a(n-1)^2-a(n-2)-a(n-3)-a(n-4), a(1)=a(2)=a(3)=a(4)=1.

1, 1, 1, 1, -2, 1, 1, 1, 1, -2, 1, 1, 1, 1, -2, 1, 1, 1, 1, -2, 1, 1, 1, 1, -2, 1, 1, 1, 1, -2, 1, 1, 1, 1, -2, 1, 1, 1, 1, -2, 1, 1, 1, 1, -2, 1, 1, 1, 1, -2, 1, 1, 1, 1, -2, 1, 1, 1, 1, -2, 1, 1, 1, 1, -2, 1, 1, 1, 1, -2, 1, 1, 1, 1, -2, 1, 1, 1, 1, -2, 1, 1, 1, 1, -2, 1, 1, 1, 1, -2, 1, 1, 1, 1, -2, 1, 1, 1, 1, -2, 1, 1, 1, 1, -2

Offset

1,5

Comments

Periodic with period 5: 1,1,1,1,-2

Links

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

Index entries for linear recurrences with constant coefficients, signature (0, 0, 0, 0, 1).

Formula

a(n)=a(n-1)^2-a(n-2)-a(n-3)-a(n-4), a(1)=a(2)=a(3)=a(4)=1

Example

a(5)=1^2-1-1-1=-2

Mathematica

a[n_]:=a[n]=a[n-1]^2-a[n-2]-a[n-3]-a[a-4]; a[1]=a[2]=a[3]=a[4]=1
LinearRecurrence[{0, 0, 0, 0, 1}, {1, 1, 1, 1, -2}, 105] (* Ray Chandler, Aug 25 2015 *)

Crossrefs

Sequence in context: A139549 A216915 A280569 * A177706 A130782 A364358

Adjacent sequences: A140342 A140343 A140344 * A140346 A140347 A140348

Keyword

sign

Author

Ben Branman, May 29 2008

Extensions

Extended by Ray Chandler, Aug 25 2015

Status

approved