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A027929 a(n) = T(n, 2*n-6), T given by A027926. 2
1, 2, 5, 13, 33, 79, 176, 365, 709, 1300, 2267, 3785, 6085, 9465, 14302, 21065, 30329, 42790, 59281, 80789, 108473, 143683, 187980, 243157, 311261, 394616, 495847, 617905, 764093, 938093, 1143994, 1386321, 1670065, 2000714 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,2

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 3..1000

Index entries for linear recurrences with constant coefficients, signature (7,-21,35,-35,21,-7,1).

FORMULA

a(n) = Sum_{k=0..3} binomial(n-k, 6-2*k). - Len Smiley, Oct 20 2001

From Colin Barker, May 01 2012: (Start)

a(n) = (3600 -3420*n +1684*n^2 -525*n^3 +115*n^4 -15*n^5 +n^6)/720.

G.f.: x^3*(1-x+x^2)*(1-4*x+7*x^2-4*x^3+x^4)/(1-x)^7. (End)

E.g.f.: (3600 - 2160*x + 720*x^2 - 120*x^3 + 30*x^4 + x^6)*exp(x)/720 - 5 + 2*x - x^2/2. - G. C. Greubel, Sep 06 2019

MAPLE

seq((3600 -3420*n +1684*n^2 -525*n^3 +115*n^4 -15*n^5 +n^6)/720, n=3..40); # G. C. Greubel, Sep 06 2019

MATHEMATICA

CoefficientList[Series[(1-x+x^2)(1-4x+7x^2-4x^3+x^4)/(1-x)^7, {x, 0, 40}], x] (* Vincenzo Librandi, Oct 18 2013 *)

PROG

(PARI) vector(40, n, m=n+2; (3600 -3420*m +1684*m^2 -525*m^3 +115*m^4 -15*m^5 +m^6)/720) \\ G. C. Greubel, Sep 06 2019

(MAGMA) [(3600 -3420*n +1684*n^2 -525*n^3 +115*n^4 -15*n^5 +n^6)/720: n in [3..40]]; // G. C. Greubel, Sep 06 2019

(Sage) [(3600 -3420*n +1684*n^2 -525*n^3 +115*n^4 -15*n^5 +n^6)/720 for n in (3..40)] # G. C. Greubel, Sep 06 2019

(GAP) List([3..40], n-> (3600 -3420*n +1684*n^2 -525*n^3 +115*n^4 -15*n^5 +n^6)/720); G. C. Greubel, Sep 06 2019

CROSSREFS

Cf. A228074.

Sequence in context: A219230 A108890 A220739 * A001659 A088921 A005183

Adjacent sequences:  A027926 A027927 A027928 * A027930 A027931 A027932

KEYWORD

nonn,easy

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified October 18 20:42 EDT 2019. Contains 328197 sequences. (Running on oeis4.)