A027968 - OEIS

A027968

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

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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