A121811 This sequence needs a meaningful name.

0, 3, 8, 19, 46, 111, 263, 622, 1473, 3485, 8246, 19512, 46166, 109230, 258441, 611480, 1446777, 3423112, 8099170, 19162842, 45339771, 107275050, 253815495, 600533909, 1420878484, 3361834590, 7954186044, 18819806248, 44528139677

Offset

1,2

Links

Table of n, a(n) for n=1..29.

Mathematica

M = N[Abs[MatrixPower[{{0, 1, 1, 1}, {1, 0, 1, 1}, {1, 1, 0, 1}, {1, 1, 1, 0}}, 1/2]]]
v[1] = {0, 1, 2, 3}
v[n_] := v[n] = M.v[n - 1]
Table[Floor[v[n][[1]]], {n, 1, 50}]

Crossrefs

Cf. A120471.

Sequence in context: A309537 A126874 A284942 * A370033 A244208 A296329

Adjacent sequences: A121808 A121809 A121810 * A121812 A121813 A121814

Keyword

nonn,uned,easy,less

Author

Roger L. Bagula, Aug 30 2006

Status

approved