id:A105348 - OEIS Search Results

Search: id:A105348

Displaying 1-1 of 1 results found.

page 1

An indicator sequence for the Jacobsthal numbers.

+0
10

1, 2, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0 (list; graph; listen)

	OFFSET	`0,2`
	COMMENT	`a(n) is the number of solutions to the Diophantine equation 2x^2-(9n+1)x+9n^2=1 where valid solutions are restricted to powers of 4. - Hieronymus Fischer (Hieronymus.Fischer(AT)gmx.de), May 17 2007`
	FORMULA	`G.f. : sum{k>=0, x^A001045(k)}` `a(n)=1+floor(log_2(3n+1))-ceiling(log_2(3n-1))=floor(log_2(3n+1))-floor(log_2(3n-2)) for n>=1. Also true: a(n)=1+A130249(n)-A130250(n))=A130253(n)-A130250(n)=A130250(n+1)-A13050(n) for n>=0. - Hieronymus Fischer (Hieronymus.Fischer(AT)gmx.de), May 17 2007`
	EXAMPLE	`a(1)=2 since J(1)=J(2)=1.`
	CROSSREFS	`For partial sums see A130253. Cf. A130249, A130250.` `Sequence in context: A075120 A111593 A111594 this_sequence A016406 A129182 A116857` `Adjacent sequences: A105345 A105346 A105347 this_sequence A105349 A105350 A105351`
	KEYWORD	`easy,nonn`
	AUTHOR	`Paul Barry (pbarry(AT)wit.ie), Apr 01 2005`

page 1

Search completed in 0.002 seconds

Last modified December 10 12:37 EST 2009. Contains 170569 sequences.

AT&T Labs Research