id:A049419 - OEIS Search Results

Search: id:A049419

Displaying 1-1 of 1 results found.

page 1

a(1) = 1; for n > 1, a(n) = number of exponential divisors of n.

+0
13

1, 1, 1, 2, 1, 1, 1, 2, 2, 1, 1, 2, 1, 1, 1, 3, 1, 2, 1, 2, 1, 1, 1, 2, 2, 1, 2, 2, 1, 1, 1, 2, 1, 1, 1, 4, 1, 1, 1, 2, 1, 1, 1, 2, 2, 1, 1, 3, 2, 2, 1, 2, 1, 2, 1, 2, 1, 1, 1, 2, 1, 1, 2, 4, 1, 1, 1, 2, 1, 1, 1, 4, 1, 1, 2, 2, 1, 1, 1, 3, 3, 1, 1, 2, 1, 1, 1, 2, 1, 2, 1, 2, 1, 1, 1, 2, 1, 2, 2, 4, 1, 1 (list; graph; listen)

	OFFSET	`1,4`
	COMMENT	`The exponential divisors of a number x = Product p(i)^r(i) are all numbers of the form Product p(i)^s(i) where s(i) divides r(i) for all i.` `Wu gives a complicated Dirichlet g.f.` `a(1) = 1 by convention. This is also required for a function to be multiplicative. - N. J. A. Sloane, Mar 03 2009`
	LINKS	`J. O. M. Pedersen, Tables of Aliquot Cycles` `Eric Weisstein's World of Mathematics, Definition` `J. Wu, Probleme de diviseurs exponentiels...`
	FORMULA	`Multiplicative with a(p^e) = tau(e). - Vladeta Jovovic (vladeta(AT)eunet.rs), Jul 23 2001`
	EXAMPLE	`a(8)=2 because 2 and 2^3 are e-divisors of 8.`
	CROSSREFS	`Cf. A049599, A061389, A051377.` `Partial sums are in A099593.` `Sequence in context: A085424 A088737 A096309 this_sequence A046951 A159631 A050377` `Adjacent sequences: A049416 A049417 A049418 this_sequence A049420 A049421 A049422`
	KEYWORD	`nonn,mult,nice`
	AUTHOR	`Yasutoshi Kohmoto (zbi74583(AT)boat.zero.ad.jp)`
	EXTENSIONS	`More terms from Jud McCranie (j.mccranie(AT)comcast.net), May 29 2000`

page 1

Search completed in 0.002 seconds

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

AT&T Labs Research