OFFSET
1,4
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 1..3000
Index entries for linear recurrences with constant coefficients, signature (0,0,4,0,0,-6,0,0,4,0,0,-1).
FORMULA
From R. J. Mathar, Jun 26 2009: (Start)
a(n) = 4*a(n-3) - 6*a(n-6) + 4*a(n-9) - a(n-12).
G.f.: -(-1-x-x^2-4*x^3+2*x^4-x^6-x^7+x^8)/((x-1)^4*(1+x+x^2)^4). (End)
a(n) = floor((n+2)/3)^((-3*(n mod 3)^2 + 5*(n mod 3) + 4)/2). - Luce ETIENNE, Mar 01 2018
MATHEMATICA
Table[{n^3, n, n^2}, {n, 20}]//Flatten (* or *) LinearRecurrence[{0, 0, 4, 0, 0, -6, 0, 0, 4, 0, 0, -1}, {1, 1, 1, 8, 2, 4, 27, 3, 9, 64, 4, 16}, 60] (* Harvey P. Dale, Feb 25 2016 *)
PROG
(Haskell)
import Data.List (transpose)
a109614 n = a109614_list !! (n-1)
a109614_list = concat $ transpose
[tail a000578_list, a000027_list, tail a000290_list]
-- Reinhard Zumkeller, Mar 14 2014
CROSSREFS
KEYWORD
AUTHOR
Mohammad K. Azarian, Aug 30 2005
STATUS
approved