OFFSET
0,4
COMMENTS
a(n+1) gives diagonal sums of Riordan array (1/(1-x),x(1+2x)) and partial sums of A052947. - Paul Barry, Jul 18 2005
LINKS
Index entries for linear recurrences with constant coefficients, signature (1,1,1,-2).
FORMULA
a(n) = a(n-1)+a(n-2)+a(n-3)-2*a(n-4) - Roger L. Bagula, Mar 25 2005
a(n+1)=sum{k=0..n, sum{j=0..floor(k/2), C(j, k-2j)2^(k-2j)}}; - Paul Barry, Jul 18 2005
MATHEMATICA
{{0, 1, 0, 0}, {0, 0, 1, 0}, {0, 0, 0, 1}, {-2, 1, 1, 1}}.{a[n - 4], a[n - 3], a[n - 2], a[n - 1]} a[0] = 0; a[1] = 1; a[2] = 1; a[3] = 2; a[n_Integer?Positive] := a[n] = a[n - 1] + a[n - 2] + a[n - 3] - 2a[n - 4]; aa = Table[a[n], {n, 0, 200}] - Roger L. Bagula, Mar 25 2005
CoefficientList[Series[x/((1-x)(1-x^2-2x^3)), {x, 0, 50}], x] (* or *) LinearRecurrence[{1, 1, 1, -2}, {0, 1, 1, 2}, 50] (* Harvey P. Dale, Aug 17 2017 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Nov 17 2002
EXTENSIONS
Edited by N. J. A. Sloane, Aug 29 2008 at the suggestion of R. J. Mathar
STATUS
approved