login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A168639
Expansion of x*(1 + x^2 - x^3) / ( (1-x)*(1-x-x^4) ).
1
0, 1, 2, 4, 5, 7, 10, 15, 21, 29, 40, 56, 78, 108, 149, 206, 285, 394, 544, 751, 1037, 1432, 1977, 2729, 3767, 5200, 7178, 9908, 13676, 18877, 26056, 35965, 49642, 68520, 94577, 130543, 180186, 248707, 343285, 473829, 654016, 902724, 1246010, 1719840, 2373857, 3276582
OFFSET
0,3
COMMENTS
Limiting ratio is: 1.38028, see A086106.
REFERENCES
R. Pallu de la Barriere, Optimal Control Theory,Dover Publications, New York,1967,pages 339-344
FORMULA
a(n)= 2*a(n-1) -a(n-2) +a(n-4) -a(n-5). - R. J. Mathar, Dec 02 2009
a(n) = A098578(n) - A098578(n-3) + A098578(n-2). - R. J. Mathar, May 23 2013
MATHEMATICA
Clear[n, m, v, M, a, b, c, K]
M = {{0, 1, 0, 0}, {0, 0, 1, 0}, {0, 0, 0, 1}, {1, 0, 0, 1}}
v[0] = {0, 0, 0, 1};
v[n_] := v[n] = M.v[n - 1] + {1, 1, 1, 1}
a = Table[v[n][[1]], {n, 0, 30}]
LinearRecurrence[{2, -1, 0, 1, -1}, {0, 1, 2, 4, 5}, 50] (* G. C. Greubel, Jul 28 2016 *)
PROG
(PARI) a(n)=([0, 1, 0, 0, 0; 0, 0, 1, 0, 0; 0, 0, 0, 1, 0; 0, 0, 0, 0, 1; -1, 1, 0, -1, 2]^n*[0; 1; 2; 4; 5])[1, 1] \\ Charles R Greathouse IV, Jul 29 2016
CROSSREFS
Cf. A098578.
Sequence in context: A241735 A092295 A277102 * A275802 A218931 A331518
KEYWORD
nonn,easy
AUTHOR
STATUS
approved