homework. answer asap thanks
2007-09-23 09:48:03 · 4 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
15 is the smallest composite number n with the property that there is only one group of order n.
(A composite number is a positive integer which is not prime (i.e., which has factors other than 1 and itself). The first few composite numbers (sometimes called "composites" for short) are 4, 6, 8, 9, 10, 12, 14, 15, 16, ... (Sloane's A002808), whose prime decompositions are summarized in the following table. Note that the number 1 is a special case which is considered to be neither composite nor prime. )
2007-09-23 09:52:38 · answer #1 · answered by barghuthi 2 · 0⤊ 0⤋
Well, it's a "triangular number". That means it's the sum of the first X natural numbers. In this case, X is 5.
1 + 2 + 3 + 4 + 5 = 15.
2007-09-23 09:53:21 · answer #2 · answered by Anonymous · 0⤊ 0⤋
It's the product of the first two odd primes (3 and 5)
Doug
2007-09-23 09:58:46 · answer #3 · answered by doug_donaghue 7 · 0⤊ 0⤋
And these primes are the lowest odd ones
Ilusion
2007-09-23 14:10:47 · answer #4 · answered by Ilusion 4 · 0⤊ 0⤋