A168074 Duplicate of A061891.

1, 1, 4, 7, 7, 10, 13, 13, 16, 19, 19, 22, 25, 25, 28, 31, 31, 34, 37, 37, 40, 43, 43, 46, 49, 49, 52, 55, 55, 58, 61, 61, 64, 67, 67, 70, 73, 73, 76, 79, 79, 82, 85, 85, 88, 91, 91, 94, 97, 97, 100, 103, 103, 106, 109, 109, 112, 115, 115, 118

Offset

0,3

Links

G. C. Greubel, Table of n, a(n) for n = 0..1000

Formula

G.f.: (1+3x^2+2x^3)/((1-x)^2*(1+x+x^2)).

a(n) = A168075(n)/(-3)^n.

a(n) = A061891(n). - Georg Fischer, Oct 14 2018

Mathematica

LinearRecurrence[{1, 0, 1, -1}, {1, 1, 4, 7}, 50] (* G. C. Greubel, Jul 09 2016 *)
CoefficientList[Series[(1 + 3 x^2 + 2 x^3) / ((1 - x)^2 (1 + x + x^2)), {x, 0, 60}], x] (* Vincenzo Librandi, Jul 10 2016 *)

Prog

(PARI) Vec((1+3*x^2+2*x^3)/((1-x)^2*(1+x+x^2)) + O(x^70)) \\ Michel Marcus, Dec 03 2014
(Magma) I:=[1, 1, 4, 7]; [n le 4 select I[n] else Self(n-1)+Self(n-3)-Self(n-4): n in [1..70]]; // Vincenzo Librandi, Jul 10 2016

Crossrefs

Sequence in context: A310930 A131432 A088744 * A061891 A310931 A310932

Adjacent sequences: A168071 A168072 A168073 * A168075 A168076 A168077

Keyword

dead

Author

Paul Barry, Nov 18 2009

Extensions

Corrected by R. J. Mathar, Dec 03 2014

Status

approved