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A027970 a(n) = T(n, 2*n-8), T given by A027960. 3
1, 4, 11, 29, 76, 196, 487, 1148, 2552, 5353, 10636, 20120, 36425, 63415, 106630, 173821, 275603, 426242, 644593, 955207, 1389626, 1987886, 2800249, 3889186, 5331634, 7221551, 9672794, 12822346, 16833919, 21901961, 28256096 (list; graph; refs; listen; history; text; internal format)
OFFSET

4,2

LINKS

Colin Barker, Table of n, a(n) for n = 4..1000

Index entries for linear recurrences with constant coefficients, signature (9,-36,84,-126,126,-84,36,-9,1).

FORMULA

Sequence satisfies an 8-degree polynomial approximating A002878.

a(n) = (-1169280 +1119312*n -517700*n^2 +148092*n^3 -26551*n^4 +2688*n^5 -70*n^6 -12*n^7 +n^8)/40320. - Colin Barker, Nov 25 2014

G.f.: x^4*(x^8-5*x^7+11*x^6-10*x^5-x^4+10*x^3-11*x^2+5*x-1) / (x-1)^9. - Colin Barker, Nov 25 2014

From G. C. Greubel, Jul 01 2019: (Start)

a(n) = A027971(n+1) - A027971(n).

E.g.f.: (1169280 + 443520*x + 80640*x^2 + 6720*x^3 +(-1169280 +725760*x  -221760*x^2 +47040*x^3 -6720*x^4 +1008*x^5 -56*x^6 +16*x^7 +x^8)*exp(x) )/8!. (End)

MATHEMATICA

Table[(-1169280 +1119312*n -517700*n^2 +148092*n^3 -26551*n^4 +2688*n^5 -70*n^6 -12*n^7 +n^8)/40320, {n, 4, 40}] (* G. C. Greubel, Jul 01 2019 *)

PROG

(PARI) Vec(x^4*(x^8-5*x^7+11*x^6-10*x^5-x^4+10*x^3-11*x^2+5*x-1)/(x-1)^9 + O(x^40)) \\ Colin Barker, Nov 25 2014

(PARI) for(n=4, 40, print1((-1169280 +1119312*n -517700*n^2 +148092*n^3 -26551*n^4 +2688*n^5 -70*n^6 -12*n^7 +n^8)/40320, ", ")) \\ G. C. Greubel, Jul 01 2019

(MAGMA) [(-1169280 +1119312*n -517700*n^2 +148092*n^3 -26551*n^4 +2688*n^5 -70*n^6 -12*n^7 +n^8)/40320: n in [4..40]]; // G. C. Greubel, Jul 01 2019

(Sage) [(-1169280 +1119312*n -517700*n^2 +148092*n^3 -26551*n^4 +2688*n^5 -70*n^6 -12*n^7 +n^8)/40320 for n in (4..40)] # G. C. Greubel, Jul 01 2019

(GAP) List([4..40], n-> (-1169280 +1119312*n -517700*n^2 +148092*n^3 -26551*n^4 +2688*n^5 -70*n^6 -12*n^7 +n^8)/40320) # G. C. Greubel, Jul 01 2019

CROSSREFS

A column of triangle A026998.

Sequence in context: A109803 A262280 A027968 * A027972 A098149 A002878

Adjacent sequences:  A027967 A027968 A027969 * A027971 A027972 A027973

KEYWORD

nonn,easy

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified September 21 08:38 EDT 2020. Contains 337268 sequences. (Running on oeis4.)