A033140 Base-4 digits are, in order, the first n terms of the periodic sequence with initial period 1,0,0.

1, 4, 16, 65, 260, 1040, 4161, 16644, 66576, 266305, 1065220, 4260880, 17043521, 68174084, 272696336, 1090785345, 4363141380, 17452565520, 69810262081, 279241048324, 1116964193296, 4467856773185, 17871427092740, 71485708370960

Offset

1,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Index entries for linear recurrences with constant coefficients, signature (4,0,1,-4).

Formula

a(n) = +4*a(n-1) +a(n-3) -4*a(n-4). G.f.: x / ( (x-1)*(4*x-1)*(1+x+x^2) ). - R. J. Mathar, Jan 08 2011

Mathematica

LinearRecurrence[{4, 0, 1, -4}, {1, 4, 16, 65}, 30] (* Vincenzo Librandi, Jun 21 2012 *)
Table[FromDigits[PadRight[{}, n, {1, 0, 0}], 4], {n, 30}] (* Harvey P. Dale, Apr 15 2018 *)

Prog

(Magma) I:=[1, 4, 16, 65]; [n le 4 select I[n] else 4*Self(n-1)+Self(n-3)-4*Self(n-4): n in [1..30]]; // Vincenzo Librandi, Jun 21 2012

Crossrefs

Sequence in context: A345365 A013149 A175065 * A181879 A243872 A052927

Adjacent sequences: A033137 A033138 A033139 * A033141 A033142 A033143

Keyword

nonn,base,easy

Author

Clark Kimberling

Status

approved