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## 112 results from messages in primenumbers

• ### Re: [PrimeNumbers] How can I Calculate the factorial for the large number

You're likely getting overflow in the calculation: m=m*i; (By overflow, I mean that the result of m*i is too big to fit into the data type of m.) What language are you using? The only mainstream language I'm familiar with that does infinite precision integer arithmetic "out of the box" is Python, and this obviously isn't Python. On 1/28/2015 6:33 AM, sis535@^\$1 [primenumbers] wrote...
Jack Brennen Jan 28
• ### Re: [PrimeNumbers] 13 successive with d(n)=12 max possible (?)

Note that 24 consecutive is impossible. To see that 24 is impossible, note that of 24 consecutive positive integers, one of them will be divisible by 24. The only multiples of 24 which have exactly 12 divisors are 72 and 96, and by inspection, neither of those works. I can't find an easy proof that 23 consecutive would be impossible. As far as 14 divisors, given any reasonable...
Jack Brennen Oct 23, 2014
• ### Re: [PrimeNumbers] What Primes look like to a layman

With respect to #3, see here: http://mathworld.wolfram.com/RiemannPrimeCountingFunction.html Which implies that there are in fact analytic formulas which basically "predict" the primes. Considering that they are based on infinite sums or integrals, they're not of much practical use to prime-hunters, but the fact that they exist at all has deep meaning for the distribution of primes...
Jack Brennen Sep 30, 2014
• ### Re: [PrimeNumbers] No new messages coming through.

As far as I can see, in both my email folder, and the yahoo group page itself, your message was the first message in 19 days. I think everyone is taking a break. :) On 11/20/2013 6:57 PM, Bill wrote: > Hi all: I am seconding Mark606's message about messages not showing up. I have no message list for this website after Nov 1, which was Marks as mentioned above. Is everyone taking a...
Jack Brennen Nov 20, 2013
• ### Re: [PrimeNumbers] emirp all bases 2 through 14?

Heuristically, I think you'd expect to find the first number that is emirp in all bases 2 through 14 somewhere in the range between: Low = 5*6^20+157 (18280792200315037) High = 2*10^16-7 (19999999999999993) Clearly, that's a big range to search though -- and you'd have to eliminate the smaller permissible ranges first: Low = your finding (14322793967831) High = 6*9^13-1...
Jack Brennen Sep 3, 2013
• ### Re: [PrimeNumbers] Re: seeking smallest 'forward concatenation prime' for power of 79

I divined the "lesser problem" from the base 10 curiosity previously linked. Basically, take all of the positive integers that can be obtained by starting with a power of 10 and concatenating consecutive increasing numbers: 10 1011 101112 10111213 1011121314 100 100101 100101102 1000 10001001 100010011002 ... The smallest such prime is the 140 digit number linked as a prime curio...
Jack Brennen Jul 30, 2013
• ### Re: [PrimeNumbers] seeking smallest 'forward concatenation prime' for power of 79

My little program to try to find a "forward concatenation prime" in base 79 tells me that no such number exists below exp(10000). Good luck finding one above that... ;) By the way, I agree with Phil that the sequence of forward concatenation primes would seem to be much more fundamental than your derived sequence. On 7/29/2013 12:01 PM, Phil Carmody wrote: > > On Mon, 7/29/13...
Jack Brennen Jul 29, 2013
• ### Re: [PrimeNumbers] Re: Polynomials

On 7/27/2013 8:53 AM, djbroadhurst wrote: > > Conversely, we may echo Keynes: > > "But this long run is a misleading guide to current affairs. > In the long run we are all dead. > Economists set themselves too easy, too useless a task if in > tempestuous seasons they can only tell us that when the storm > is past the ocean is flat again." > John Maynard Keynes (1883-1946), in > "A...
Jack Brennen Jul 27, 2013