A331413 a(n) = 2*a(n-1) + a(n-2) + a(n-3) + a(n-4), a(0)=4, a(1)=2, a(2)=6, a(3)=17.

4, 2, 6, 17, 46, 117, 303, 786, 2038, 5282, 13691, 35488, 91987, 238435, 618036, 1601982, 4152422, 10763297, 27899034, 72315769, 187446291, 485870682, 1259402458, 3264437658, 8461594747, 21932900292, 56851235447, 147361403591, 381968537668, 990082614666, 2566346406038

Offset

0,1

Links

Michael De Vlieger, Table of n, a(n) for n = 0..2417

Index entries for linear recurrences with constant coefficients, signature (2,1,1,1).

Formula

G.f.: (x^3 + 2*x^2 + 6*x - 4)/(x^4 + x^3 + x^2 + 2*x - 1). - Chai Wah Wu, Jan 16 2020

Mathematica

LinearRecurrence[{2, 1, 1, 1}, {4, 2, 6, 17}, 31] (* Michael De Vlieger, Jan 16 2020 *)
CoefficientList[Series[(x^3 + 2 x^2 + 6 x - 4)/(x^4 + x^3 + x^2 + 2 x - 1), {x, 0, 30}], x] (* Michael De Vlieger, Jan 17 2020 *)

Crossrefs

Sequence in context: A083760 A073597 A099507 * A019104 A019119 A019181

Adjacent sequences: A331410 A331411 A331412 * A331414 A331415 A331416

Keyword

nonn

Author

Michael De Vlieger, Jan 16 2020

Extensions

Deleted certain dangerous or potentially dangerous links. - N. J. A. Sloane, Jan 30 2021

Status

approved