A173711 Nonnegative integers, six even followed by two odd.

0, 0, 0, 0, 0, 0, 1, 1, 2, 2, 2, 2, 2, 2, 3, 3, 4, 4, 4, 4, 4, 4, 5, 5, 6, 6, 6, 6, 6, 6, 7, 7, 8, 8, 8, 8, 8, 8, 9, 9, 10, 10, 10, 10, 10, 10, 11, 11, 12, 12, 12, 12, 12, 12, 13, 13, 14, 14, 14, 14, 14, 14, 15, 15, 16, 16, 16, 16, 16, 16, 17, 17

Offset

0,9

Links

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

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

Formula

a(n) = A180969(3,n) + A180969(3,n+2).

G.f.: x^6 / ((x+1)*(x^4+1)*(x-1)^2).

a(n) = a(n-1) + a(n-2) - a(n-3) - a(n-4) + a(n-5) + a(n-6) - a(n-7). - G. C. Greubel, Nov 23 2016

Mathematica

LinearRecurrence[{1, 1, -1, -1, 1, 1, -1}, {0, 0, 0, 0, 0, 0, 1}, 50] (* G. C. Greubel, Nov 23 2016 *)
CoefficientList[Series[x^6 / ((x + 1) (x^4 + 1) (x - 1)^2), {x, 0, 100}], x] (* Vincenzo Librandi, Nov 24 2016 *)
Table[If[EvenQ[n], PadRight[{}, 6, n], {n, n}], {n, 0, 20}]//Flatten (* Harvey P. Dale, Nov 07 2020 *)

Prog

(Magma) I:=[0, 0, 0, 0, 0, 0, 1]; [n le 7 select I[n] else Self(n-1) + Self(n-2) - Self(n-3)-Self(n-4)+Self(n-5)+Self(n-6)-Self(n-7): n in [1..80]]; // Vincenzo Librandi, Nov 24 2016

Crossrefs

Sequence in context: A127238 A072114 A090621 * A236678 A029378 A053278

Adjacent sequences: A173708 A173709 A173710 * A173712 A173713 A173714

Keyword

easy,nonn

Author

Adriano Caroli, Nov 25 2010

Status

approved