30: Difference between revisions

Revision as of 01:02, 23 June 2012

This article is about a particular natural number.|View all articles on particular natural numbers

The factorization is as follows, with factors 2, 3, and 5:

$30=2^{1}\cdot 3^{1}\cdot 5^{1}=2\cdot 3\cdot 5$

Property or family	Parameter values	First few members of the family	Proof of satisfaction/membership/containment
Giuga number: composite number $n$ such that $p$ divides $(n/p)-1$ for all prime divisors $p$ of $n$ .	first Giuga number	30, 858, 1722, 66198, [SHOW MORE] 2214408306, 24423128562, 432749205173838, 14737133470010574, 550843391309130318, 244197000982499715087866346, 554079914617070801288578559178, 1910667181420507984555759916338506 View list on OEIS	check on each prime divisor: 2 divides (30/2) - 1 = 14 3 divides (30/3) - 1 = 9 5 divides 30/5 - 1 = 5
primorial: product of the first few prime numbers	product of the first three prime numbers (if we start the indexing from the zeroth primorial, which is an empty product and evaluates to 1, it is the fourth in the list)	1, 2, 6, 30, 210, 2310 View list on OEIS	The first three primes are 2,3,5, and their product is 30.

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 | [[Giuga number]]: composite number <math>n</math> such that <math>p</math> divides <math>(n/p) - 1</math> for all prime divisors <math>p</math> of <math>n</math>. || first Giuga number || {{#lst:Giuga number|list}} || check on each prime divisor:<br>2 divides (30/2) - 1 = 14<br>3 divides (30/3) - 1 = 9<br>5 divides 30/5 - 1 = 5
 |-
-| [[primorial]]: product of the first few prime numbers || third primorial: product of the first three prime numbers || {{#lst:primorial|list}} || The first three primes are 2,3,5, and their product is 30.
+| [[primorial]]: product of the first few prime numbers || product of the first three prime numbers (if we start the indexing from the zeroth primorial, which is an empty product and evaluates to 1, it is the ''fourth'' in the list) || {{#lst:primorial|list}} || The first three primes are 2,3,5, and their product is 30.
 |}