A084861 Expansion of (1-3x+4x^2-3x^3+x^4)/(1-2x)^2.

1, 1, 4, 9, 21, 48, 108, 240, 528, 1152, 2496, 5376, 11520, 24576, 52224, 110592, 233472, 491520, 1032192, 2162688, 4521984, 9437184, 19660800, 40894464, 84934656, 176160768, 364904448, 754974720, 1560281088, 3221225472

Offset

0,3

Comments

Partial sums give A084860. Binomial transform of signed version of A008795.

Links

Table of n, a(n) for n=0..29.

Index entries for linear recurrences with constant coefficients, signature (4,-4).

Formula

a(n) = 3(n+3)2^(n-4), n>2.

Mathematica

CoefficientList[Series[(1-3x+4x^2-3x^3+x^4)/(1-2x)^2, {x, 0, 40}], x] (* or *) LinearRecurrence[{4, -4}, {1, 1, 4, 9, 21}, 40] (* Harvey P. Dale, Nov 25 2020 *)

Crossrefs

Sequence in context: A027973 A348407 A103040 * A122498 A132750 A297296

Adjacent sequences: A084858 A084859 A084860 * A084862 A084863 A084864

Keyword

easy,nonn

Author

Paul Barry, Jun 12 2003

Status

approved