A037505 Base-4 digits are, in order, the first n terms of the periodic sequence with initial period 1,2,0.

1, 6, 24, 97, 390, 1560, 6241, 24966, 99864, 399457, 1597830, 6391320, 25565281, 102261126, 409044504, 1636178017, 6544712070, 26178848280, 104715393121, 418861572486, 1675446289944, 6701785159777, 26807140639110, 107228562556440

Offset

1,2

Links

Table of n, a(n) for n=1..24.

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

Index entries for 2-automatic sequences.

Formula

G.f.: x*(1+2*x) / ( (x-1)*(4*x-1)*(1+x+x^2) ). - R. J. Mathar, Apr 27 2015

A007090(a(n)) = A037511(n). - R. J. Mathar, Apr 27 2015

Mathematica

Module[{nn=30, c}, c=PadRight[{}, nn, {1, 2, 0}]; Table[FromDigits[Take[c, n], 4], {n, nn}]] (* Harvey P. Dale, Mar 06 2013 *)

Prog

(PARI) a(n)=([0, 1, 0, 0; 0, 0, 1, 0; 0, 0, 0, 1; -4, 1, 0, 4]^(n-1)*[1; 6; 24; 97])[1, 1] \\ Charles R Greathouse IV, Feb 13 2017

Crossrefs

Sequence in context: A002023 A164908 A290911 * A048179 A117614 A037688

Adjacent sequences: A037502 A037503 A037504 * A037506 A037507 A037508

Keyword

nonn,base,easy

Author

Clark Kimberling

Status

approved