A145028 a(n) = a(n-1) + a(n-2) + a(n-3) + a(n-4).

1, 2, 3, 4, 10, 19, 36, 69, 134, 258, 497, 958, 1847, 3560, 6862, 13227, 25496, 49145, 94730, 182598, 351969, 678442, 1307739, 2520748, 4858898, 9365827, 18053212, 34798685, 67076622, 129294346, 249222865, 480392518, 925986351, 1784896080

Offset

1,2

Links

Table of n, a(n) for n=1..34.

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

Formula

G.f.: x*(1-x)*(1+2*x+2*x^2)/(1-x-x^2-x^3-x^4). - Colin Barker, Jan 11 2012

Mathematica

LinearRecurrence[{1, 1, 1, 1}, {1, 2, 3, 4}, 30]

Crossrefs

Sequence in context: A135432 A108364 A346489 * A306107 A229545 A085932

Adjacent sequences: A145025 A145026 A145027 * A145029 A145030 A145031

Keyword

nonn,easy

Author

Vladimir Joseph Stephan Orlovsky, Sep 30 2008

Status

approved