here is an intresting question that i made..but i donno the ans..
help me out..
2007-01-04 02:13:42 · 5 answers · asked by alan john 1 in Science & Mathematics ➔ Mathematics
Quoting directly from the web page below : "The form n!-1 is prime for n = 3, 4, 6, 7, 12, 14, 30, 32, 33, 38, 94, 166, 324, 379, 469, 546, 974, 1963, 3507, 3610 and 6917."
6917! - 1 has 23560 digits. There are no more such primes up to 10000! - 1.
Chris Caldwell's Prime Pages are the best resource on the whole worldwide web for questions related to prime numbers.
2007-01-04 04:44:16 · answer #1 · answered by Anonymous · 0⤊ 0⤋
Well, for starters, n=3 and n=4 produce prime numbers of 5 and 23, respectively. Try it out on Excel and see if a pattern emerges.
2007-01-04 02:25:41 · answer #2 · answered by ironduke8159 7 · 0⤊ 0⤋
Nobody knows even if such n's are finitely many or not... There are no easy questions with prime numbers apart from obvious ones. This is not one of them.
2007-01-04 02:58:30 · answer #3 · answered by gianlino 7 · 0⤊ 1⤋
The factorial of n can NOT be a prime. Because the primes are sparser than the natural numbers you will have a composite between them. As an aside: even twin primes have an even number between them. All twin primes except (3, 5) are of the form 6n +/- 1 (http://mathworld.wolfram.com/TwinPrimes.html).
2007-01-04 02:41:54 · answer #4 · answered by Boehme, J 2 · 0⤊ 4⤋
when n=3
n!=6
n!-1=5
so there may be infinite of such prime number
2007-01-04 02:18:40 · answer #5 · answered by miinii 3 · 0⤊ 0⤋