id:A003958 - OEIS Search Results

Search: id:A003958

Displaying 1-1 of 1 results found.

page 1

Fully multiplicative with a(p) = p-1 for prime p.

+0
26

1, 1, 2, 1, 4, 2, 6, 1, 4, 4, 10, 2, 12, 6, 8, 1, 16, 4, 18, 4, 12, 10, 22, 2, 16, 12, 8, 6, 28, 8, 30, 1, 20, 16, 24, 4, 36, 18, 24, 4, 40, 12, 42, 10, 16, 22, 46, 2, 36, 16, 32, 12, 52, 8, 40, 6, 36, 28, 58, 8, 60, 30, 24, 1, 48, 20, 66, 16, 44, 24, 70, 4, 72, 36, 32, 18, 60, 24, 78, 4, 16 (list; graph; listen)

	OFFSET	`1,3`
	COMMENT	`a(n) = A000010(n) iff n is square-free (see A005117). - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Nov 05 2004`
	LINKS	`T. D. Noe, Table of n, a(n) for n=1..1000`
	FORMULA	`If n = Product p(k)^e(k) then a(n) = Product (p(k)-1)^e(k).` `Multiplicative with a(p^e) = (p-1)^e. - David W. Wilson (davidwwilson(AT)comcast.net), Aug 01, 2001.`
	PROGRAM	`(PARI) a(n)=if(n<1, 0, direuler(p=2, n, 1/(1-p*X+X))[n]) (from R. Stephan)`
	CROSSREFS	`Cf. A003959.` `Adjacent sequences: A003955 A003956 A003957 this_sequence A003959 A003960 A003961` `Sequence in context: A141564 A046791 A125131 this_sequence A082729 A076686 A114810`
	KEYWORD	`nonn,mult,nice`
	AUTHOR	`Marc LeBrun (mlb(AT)well.com)`

page 1

Search completed in 0.002 seconds

Last modified November 8 20:39 EST 2009. Contains 166234 sequences.

AT&T Labs Research