A081681 A sum of decreasing powers.

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

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

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. 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