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A027968 a(n) = T(n, 2*n-6), T given by A027960. 3
1, 4, 11, 29, 73, 171, 370, 743, 1397, 2482, 4201, 6821, 10685, 16225, 23976, 34591, 48857, 67712, 92263, 123805, 163841, 214103, 276574, 353511, 447469, 561326, 698309, 862021, 1056469, 1286093, 1555796, 1870975, 2237553 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,2

LINKS

G. C. Greubel, 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

From Ralf Stephan, Feb 07 2004: (Start)

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

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

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

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

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)

MATHEMATICA

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 *)

PROG

(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

(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

(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

(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

CROSSREFS

A column of triangle A026998.

Sequence in context: A131046 A109803 A262280 * A027970 A027972 A098149

Adjacent sequences:  A027965 A027966 A027967 * A027969 A027970 A027971

KEYWORD

nonn

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified August 8 14:36 EDT 2020. Contains 336298 sequences. (Running on oeis4.)