id:A027711 - OEIS Search Results

Search: id:A027711

Displaying 1-1 of 1 results found.

page 1

Number of binary sequences of length n with an even number of ones, at least two of the ones being contiguous.

+0
1

0, 1, 2, 4, 9, 21, 47, 101, 212, 440, 907, 1859, 3791, 7699, 15586, 31476, 63445, 127689, 256671, 515433, 1034248, 2073968, 4156791, 8327911, 16679007, 33395527, 66851750, 133801708, 267762321, 535781757, 1071979535 (list; graph; listen)

	OFFSET	`1,3`
	FORMULA	`x^2(1-2x+x^2+x^3)/((1-x)(1-x-x^2)(1-x+x^2)).`
	CROSSREFS	`Sequence in context: A093698 A091619 A061439 this_sequence A084634 A137256 A051164` `Adjacent sequences: A027708 A027709 A027710 this_sequence A027712 A027713 A027714`
	KEYWORD	`nonn`
	AUTHOR	`R. K. Guy (rkg(AT)cpsc.ucalgary.ca)`

page 1

Search completed in 0.002 seconds

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

AT&T Labs Research