id:A097122 - OEIS Search Results

Search: id:A097122

Displaying 1-1 of 1 results found.

page 1

Expansion of (1-x)^2/((1-x)^3-3x^3).

+0
2

1, 1, 1, 4, 13, 31, 70, 169, 421, 1036, 2521, 6139, 14998, 36661, 89545, 218644, 533941, 1304071, 3184966, 7778449, 18996733, 46394716, 113307745, 276726019, 675833686, 1650553981, 4031064961, 9844867684, 24043624093, 58720529071 (list; graph; listen)

	OFFSET	`0,4`
	FORMULA	`G.f.: (1-2x+x^2)/(1-3x+3x^2-4x^3); a(n)=3a(n-1)-3a(n-2)+4a(n-3); a(n)=sum{k=0..floor(n/3), binomial(n, 3k)3^k }.`
	CROSSREFS	`Cf. A024493, A052101.` `Sequence in context: A097120 A098536 A011937 this_sequence A116411 A106337 A027998` `Adjacent sequences: A097119 A097120 A097121 this_sequence A097123 A097124 A097125`
	KEYWORD	`easy,nonn`
	AUTHOR	`Paul Barry (pbarry(AT)wit.ie), Jul 25 2004`

page 1

Search completed in 0.002 seconds

Last modified July 25 07:41 EDT 2008. Contains 142293 sequences.

AT&T Labs Research