A329505 Expansion of (1 + x)*(1 + 2*x - x^2) / (1 - x).

1, 4, 5, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4

Offset

0,2

Links

Table of n, a(n) for n=0..84.

Index entries for linear recurrences with constant coefficients, signature (1).

Formula

a(n) = 4 for n>=3.

Prog

(PARI) Vec((1 + x)*(1 + 2*x - x^2) / (1 - x) + O(x^80)) \\ Colin Barker, Nov 21 2019

Crossrefs

Row 2 of array in A329504.

Essentially the same as A000655.

Sequence in context: A031349 A200605 A036444 * A125583 A196619 A343954

Adjacent sequences: A329502 A329503 A329504 * A329506 A329507 A329508

Keyword

nonn,easy

Author

N. J. A. Sloane, Nov 20 2019

Status

approved