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A027968 a(n) = T(n, 2*n-6), T given by A027960. 3

%I

%S 1,4,11,29,73,171,370,743,1397,2482,4201,6821,10685,16225,23976,34591,

%T 48857,67712,92263,123805,163841,214103,276574,353511,447469,561326,

%U 698309,862021,1056469,1286093,1555796,1870975,2237553

%N a(n) = T(n, 2*n-6), T given by A027960.

%H G. C. Greubel, <a href="/A027968/b027968.txt">Table of n, a(n) for n = 3..1000</a>

%H <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (7,-21,35,-35,21,-7,1).

%F From _Ralf Stephan_, Feb 07 2004: (Start)

%F G.f.: x^3*(1 -3*x +4*x^2 +x^3 -4*x^4 +3*x^5 -x^6)/(1-x)^7.

%F a(n) = A027969(n+1) - A027969(n). (End)

%F From _G. C. Greubel_, Jul 01 2019: (Start)

%F a(n) = (-7920 +7548*n -3176*n^2 +735*n^3 -65*n^4 -3*n^5 +n^6)/720.

%F E.g.f.: (7920 +2880*x +360*x^2 -(7920 -5040*x +1440*x^2 -360*x^3 +30*x^4 -12*x^5 -x^6)*exp(x))/6!. (End)

%t Table[(-7920 +7548*n -3176*n^2 +735*n^3 -65*n^4 -3*n^5 +n^6)/720, {n,3,40}] (* _G. C. Greubel_, Jul 01 2019 *)

%o (PARI) for(n=3,40, print1((-7920 +7548*n -3176*n^2 +735*n^3 -65*n^4 -3*n^5 +n^6)/720, ", ")) \\ _G. C. Greubel_, Jul 01 2019

%o (MAGMA) [(-7920 +7548*n -3176*n^2 +735*n^3 -65*n^4 -3*n^5 +n^6)/720: n in [3..40]]; // _G. C. Greubel_, Jul 01 2019

%o (Sage) [(-7920 +7548*n -3176*n^2 +735*n^3 -65*n^4 -3*n^5 +n^6)/720 for n in (3..40)] # _G. C. Greubel_, Jul 01 2019

%o (GAP) List([3..40], n-> (-7920 +7548*n -3176*n^2 +735*n^3 -65*n^4 -3*n^5 +n^6)/720) # _G. C. Greubel_, Jul 01 2019

%Y A column of triangle A026998.

%K nonn

%O 3,2

%A _Clark Kimberling_

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Last modified September 22 00:42 EDT 2020. Contains 337276 sequences. (Running on oeis4.)