A081681 a(n) = (8^n-7^n-6^n-5^n+4*4^n)/2.

1, 3, 9, 42, 399, 4578, 49299, 490542, 4602159, 41440938, 362614539, 3108879942, 26262187719, 219426920898, 1818214750179, 14970201491742, 122642764106079, 1000774210138458, 8140442567772219, 66044479587885942, 534691055242021239

Offset

0,2

Comments

Binomial transform of A081680.

Links

Table of n, a(n) for n=0..20.

Index entries for linear recurrences with constant coefficients, signature (30,-355,2070,-5944,6720).

Formula

G.f.: -(2068*x^4-1233*x^3+274*x^2-27*x+1)/((4*x-1)*(5*x-1)*(6*x-1)*(7*x-1)*(8*x-1)). [Colin Barker, Sep 07 2012]

Mathematica

LinearRecurrence[{30, -355, 2070, -5944, 6720}, {1, 3, 9, 42, 399}, 30] (* Harvey P. Dale, Apr 18 2020 *)

Crossrefs

Cf. A081680, A081682.

Sequence in context: A009402 A009584 A013562 * A281940 A141774 A141349

Adjacent sequences: A081678 A081679 A081680 * A081682 A081683 A081684

Keyword

easy,nonn

Author

Paul Barry, Mar 30 2003

Status

approved