id:A109220 - OEIS Search Results

Search: id:A109220

Displaying 1-1 of 1 results found.

page 1

Expansion of (1+x-x^2)/(1-2x-2x^2+x^4).

+0
1

1, 3, 7, 20, 53, 143, 385, 1036, 2789, 7507, 20207, 54392, 146409, 394095, 1060801, 2855400, 7685993, 20688691, 55688567, 149899116, 403489373, 1086088287, 2923466753, 7869210964, 21181866061, 57016065763, 153472396895 (list; graph; listen)

	OFFSET	`0,2`
	COMMENT	`Transform of 2^n under matrix A108756.`
	FORMULA	`a(n)=2a(n-1)+2a(n-2)-a(n-4); a(n)=a(n)=sum{k=0..n, binomial(floor((n+k+1)/2)+k, floor((n+k)/2)-k)*2^k}.`
	CROSSREFS	`Sequence in context: A066315 A058499 A003097 this_sequence A018034 A000227 A058737` `Adjacent sequences: A109217 A109218 A109219 this_sequence A109221 A109222 A109223`
	KEYWORD	`easy,nonn`
	AUTHOR	`Paul Barry (pbarry(AT)wit.ie), Jun 22 2005`

page 1

Search completed in 0.002 seconds

Last modified November 25 20:09 EST 2009. Contains 167514 sequences.

AT&T Labs Research