id:A069780 - OEIS Search Results

Search: id:A069780

Displaying 1-1 of 1 results found.

page 1

a(n)=GCD[d(n^3),d(n)].

+0
6

1, 2, 2, 1, 2, 4, 2, 2, 1, 4, 2, 2, 2, 4, 4, 1, 2, 2, 2, 2, 4, 4, 2, 8, 1, 4, 2, 2, 2, 8, 2, 2, 4, 4, 4, 1, 2, 4, 4, 8, 2, 8, 2, 2, 2, 4, 2, 2, 1, 2, 4, 2, 2, 8, 4, 8, 4, 4, 2, 4, 2, 4, 2, 1, 4, 8, 2, 2, 4, 8, 2, 2, 2, 4, 2, 2, 4, 8, 2, 2, 1, 4, 2, 4, 4, 4, 4, 8, 2, 4, 4, 2, 4, 4, 4, 4, 2, 2, 2, 1, 2, 8, 2, 8, 8 (list; graph; listen)

	OFFSET	`1,2`
	FORMULA	`a(n)=GCD[A000005(n^3), A000005(n)]`
	EXAMPLE	`Terms are usually powers of 2. Smallest number m such that A069780(m)=2^n is A037992(n). The first n such that a(n) is not a power of 2 equals 432: a(432)=GCD[d[80621568],d[432]]=GCD[130,20]=10.`
	MATHEMATICA	`Table[GCD[DivisorSigma[0, n^3], DivisorSigma[0, n]], {n, 1, 500}]`
	CROSSREFS	`Cf. A000005, A037992, A069781, A069782.` `Sequence in context: A156260 A056671 A055076 this_sequence A066954 A144925 A029262` `Adjacent sequences: A069777 A069778 A069779 this_sequence A069781 A069782 A069783`
	KEYWORD	`easy,nonn`
	AUTHOR	`Labos E. (labos(AT)ana.sote.hu), Apr 08 2002`

page 1

Search completed in 0.002 seconds

Last modified November 23 17:09 EST 2009. Contains 167438 sequences.

AT&T Labs Research