This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A052900 Expansion of (1-x)/(1-x-3x^3). 1
 1, 0, 0, 3, 3, 3, 12, 21, 30, 66, 129, 219, 417, 804, 1461, 2712, 5124, 9507, 17643, 33015, 61536, 114465, 213510, 398118, 741513, 1382043, 2576397, 4800936, 8947065, 16676256, 31079064, 57920259, 107949027, 201186219, 374946996 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 LINKS INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 876 FORMULA G.f.: (-1+x)/(-1+x+3*x^3) Recurrence: {a(1)=0, a(0)=1, a(2)=0, 3*a(n)+a(n+2)-a(n+3)=0} Sum(-1/85*(2+9*_alpha^2-29*_alpha)*_alpha^(-1-n), _alpha=RootOf(-1+_Z+3*_Z^3)) MAPLE spec := [S, {S=Sequence(Prod(Union(Z, Z, Z), Sequence(Z), Z, Z))}, unlabeled]: seq(combstruct[count](spec, size=n), n=0..20); CROSSREFS a(n) = 3*A084386(n-3), also first differences of A084386. Sequence in context: A225073 A152575 A170851 * A024947 A291407 A147823 Adjacent sequences:  A052897 A052898 A052899 * A052901 A052902 A052903 KEYWORD easy,nonn AUTHOR encyclopedia(AT)pommard.inria.fr, Jan 25 2000 EXTENSIONS More terms from James A. Sellers, Jun 06 2000 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified August 21 18:26 EDT 2019. Contains 326168 sequences. (Running on oeis4.)