A038740 a(n) = T(n,n-3), array T as in A038738.

1, 9, 47, 188, 643, 1993, 5798, 16193, 44068, 118013, 312974, 825277, 2169045, 5690426, 14913861, 39066661, 102306471, 267879086, 701364436, 1836256726, 4807458872, 12586185670, 32951178868, 86267449214, 225851287529

Offset

3,2

Links

Table of n, a(n) for n=3..27.

Index entries for linear recurrences with constant coefficients, signature (9,-34,71,-90,71,-34,9,-1).

Formula

G.f.: x^3/((1-3*x+x^2)*(1-x)^6).

a(3)=1, a(4)=9, a(5)=47, a(6)=188, a(7)=643, a(8)=1993, a(9)=5798, a(10)=16193, a(n) = 9*a(n-1)-34*a(n-2)+71*a(n-3)-90*a(n-4)+71*a(n-5)-34*a(n-6)+9*a(n-7)-a(n-8). - Harvey P. Dale, Jan 06 2012

Mathematica

Drop[CoefficientList[Series[x^3/((1-3x+x^2)(1-x)^6), {x, 0, 30}], x], 3] (* or *) LinearRecurrence[ {9, -34, 71, -90, 71, -34, 9, -1}, {1, 9, 47, 188, 643, 1993, 5798, 16193}, 30] (* Harvey P. Dale, Jan 06 2012 *)

Crossrefs

Cf. A038738.

Sequence in context: A391664 A100790 A055250 * A225428 A163614 A207318

Adjacent sequences: A038737 A038738 A038739 * A038741 A038742 A038743

Keyword

nonn,easy

Author

Clark Kimberling, May 02 2000

Status

approved