A106250 Expansion of (1-x+x^2+x^3)/(1-x-x^5+x^6).

1, 0, 1, 2, 2, 3, 2, 3, 4, 4, 5, 4, 5, 6, 6, 7, 6, 7, 8, 8, 9, 8, 9, 10, 10, 11, 10, 11, 12, 12, 13, 12, 13, 14, 14, 15, 14, 15, 16, 16, 17, 16, 17, 18, 18, 19, 18, 19, 20, 20, 21, 20, 21, 22, 22, 23, 22, 23, 24, 24, 25, 24, 25, 26, 26, 27, 26, 27, 28, 28, 29, 28, 29, 30, 30, 31, 30

Offset

0,4

Links

Table of n, a(n) for n=0..76.

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

Formula

G.f.: (1-x+x^2+x^3)/(1-x-x^5+x^6)=(1+x^2+2x^3+2x^4+x^5+2x^6+x^7)/(1-x^5)^2; a(n)=sum{k=0..n, -mu(k mod 5)}.

Mathematica

CoefficientList[Series[(1-x+x^2+x^3)/(1-x-x^5+x^6), {x, 0, 120}], x] (* or *) LinearRecurrence[{1, 0, 0, 0, 1, -1}, {1, 0, 1, 2, 2, 3}, 121] (* Harvey P. Dale, Apr 26 2011 *)

Crossrefs

Cf. A008611.

Sequence in context: A322630 A277194 A172151 * A029248 A085916 A286535

Adjacent sequences: A106247 A106248 A106249 * A106251 A106252 A106253

Keyword

easy,nonn

Author

Paul Barry, Apr 27 2005

Status

approved