id:A067397 - OEIS Search Results

Search: id:A067397

Displaying 1-1 of 1 results found.

page 1

Maximal power of 3 which divides n-th Catalan number.

+0
1

0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 2, 2, 2, 1, 1, 1, 1, 1, 1, 2, 2, 2, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 3, 3, 3, 2, 2, 2, 2, 2, 2, 3, 3, 3, 1, 1, 1, 1, 1, 1, 2, 2, 2, 1, 1, 1, 1, 1, 1, 3, 3, 3, 2, 2, 2, 2, 2, 2, 3, 3, 3, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 2, 2, 2, 1, 1, 1, 1, 1, 1, 2 (list; graph; listen)

	OFFSET	`0,15`
	LINKS	`H. Bottomley, Illustration for A067397`
	FORMULA	`Let k=floor[log3(n)], i.e. 3^k<=n<3^(k+1): if (3/2)3^k<n<(5/2)3^k then a(n)=a(n-3^k)+1, if n=3*3^k-1 then a(n)=a(n-3^k)-1=0, otherwise a(n)=a(n-3^k) [starting with a(0)=0, so a(3^k)=0].`
	EXAMPLE	`a(13)=0 since Catalan(13)=742900 which is not divisible by 3; a(14)=2 since Catalan(14)=2674440 which is divisible by 9 but not by 27.`
	CROSSREFS	`Cf. A000108, A048881.` `Adjacent sequences: A067394 A067395 A067396 this_sequence A067398 A067399 A067400` `Sequence in context: A030599 A102679 A025146 this_sequence A080586 A128522 A025454`
	KEYWORD	`nonn`
	AUTHOR	`Henry Bottomley (se16(AT)btinternet.com), Jan 22 2002`

page 1

Search completed in 0.002 seconds

Last modified October 5 16:50 EDT 2008. Contains 144613 sequences.

AT&T Labs Research