A037639 Base 4 digits are, in order, the first n terms of the periodic sequence with initial period 2,3,1.

2, 11, 45, 182, 731, 2925, 11702, 46811, 187245, 748982, 2995931, 11983725, 47934902, 191739611, 766958445, 3067833782, 12271335131, 49085340525, 196341362102, 785365448411, 3141461793645, 12565847174582, 50263388698331

Offset

1,1

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

G.f.: x*(x+2)*(1+x) / ( (x-1)*(4*x-1)*(1+x+x^2) ). - R. J. Mathar, Nov 21 2011

a(n) = 4*a(n-1) + a(n-3) - 4*a(n-4). - Vincenzo Librandi, Jun 17 2012

Mathematica

  LinearRecurrence[{4, 0, 1, -4}, {2, 11, 45, 182}, 40] (* Vincenzo Librandi, Jun 17 2012 *)

Prog

(Magma) I:=[2, 11, 45, 182]; [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 17 2012

Crossrefs

Sequence in context: A209604 A120279 A037751 * A319428 A000176 A042927

Adjacent sequences: A037636 A037637 A037638 * A037640 A037641 A037642

Keyword

nonn,base

Author

Clark Kimberling

Status

approved