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A173711
Nonnegative integers, six even followed by two odd.
2
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
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
KEYWORD
easy,nonn
AUTHOR
Adriano Caroli, Nov 25 2010
STATUS
approved