A099848 - OEIS

This site is supported by donations to The OEIS Foundation.

A099848

All natural numbers occur in their order as many times as they have ordered prime factorizations.

1, 2, 3, 4, 5, 6, 6, 7, 8, 9, 10, 10, 11, 12, 12, 12, 13, 14, 14, 15, 15, 16, 17, 18, 18, 18, 19, 20, 20, 20, 21, 21, 22, 22, 23, 24, 24, 24, 24, 25, 26, 26, 27, 28, 28, 28, 29, 30, 30, 30, 30, 30, 30, 31, 32, 33, 33, 34, 34, 35, 35, 36, 36, 36, 36, 36, 36, 37, 38, 38, 39, 39, 40 (list; graph; refs; listen; history; text; internal format)

	OFFSET	`1,2`
	COMMENTS	`n occurs exactly once iff n is a prime power (A000961);` `n occurs exactly twice iff n is a semiprime with distinct factors (A006881);` `a(A099849(n) - k) = n for 0 <= k < A008480(n).`
	LINKS	`Table of n, a(n) for n=1..73.` `Eric Weisstein's World of Mathematics, Prime Factorization`
	EXAMPLE	`n = 12: A008480(12) = #{322, 232, 223} = 3, therefore 12 occurs three times.`
	CROSSREFS	`Cf. A008480.` `Sequence in context: A071520 A195918 A176842 * A082287 A210062 A006164` `Adjacent sequences: A099845 A099846 A099847 * A099849 A099850 A099851`
	KEYWORD	`nonn`
	AUTHOR	`Reinhard Zumkeller, Oct 27 2004`
	STATUS	`approved`

Content is available under The OEIS End-User License Agreement .

Last modified May 20 08:47 EDT 2013. Contains 225458 sequences.