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Talk:Zumkeller numbers: Difference between revisions
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→Where to find count of Zumkeller to verify solutions.Is there a constant ratio 0.228...?: new timings
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if (n % 2 || d.size() >= 24)
return true;</pre>
99504 has 30 divisors and is not a
<lang go>func main() {
fmt.Println("The first 220 Zumkeller numbers are:")
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99500 99504 99510 99512 99516 </pre>
Checked the first 100,000
First
<pre>
Div
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I took a look and I'm not getting those numbers in the output. Can I see how you unit tested this? I'm not sure why that would matter though... my best guess is an OS dtype issue causing overflow but that seems unlikely. What IDE/OS did you run this on?--[[User:Mckann|Mckann]] ([[User talk:Mckann|talk]]) 03:35, 12 May 2021 (UTC)
: I think the overflow will happen with 32 Bit aka uint.<br>If you change d.size to >30-Bit it will take a while and find 99504 to be a non-
if (n % 2 || d.size() > 30)
return true;</lang>
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:: There is no.<BR>In '[[oeis:A083207|OEIS:A083207 - Zumkeller numbers]] someone stated and checked <pre>All 205283 odd abundant numbers less than 10^8 that have even abundance are Zumkeller numbers. - T. D. Noe, Nov 14 2010</pre> something one can use.
Oh I see. It works, empirically, for N >> max
== Where to find count of
I have modified the program to run up to 1E9.On AMD 2200G Linux 64-bit
<pre>
Start 1 at 1
100000000 tested found 22879037 ratio 0.2287904 recursion 1.101 runtime 9.777 s
200000000 tested found 45744040 ratio 0.2287202 recursion 1.116 runtime 10.640 s
300000000 tested found 68603020 ratio 0.2286767 recursion 1.171 runtime 11.159 s
400000000 tested found 91458844 ratio 0.2286471 recursion 1.230 runtime 11.506 s
500000000 tested found 114316149 ratio 0.2286323 recursion 1.283 runtime 11.770 s
600000000 tested found 137176153 ratio 0.2286269 recursion 1.332 runtime 20.701 s
700000000 tested found 160037821 ratio 0.2286255 recursion 2.834 runtime 22.288 s
800000000 tested found 182899550 ratio 0.2286244 recursion 2.786 runtime 13.064 s
900000000 tested found 205760422 ratio 0.2286227 recursion 2.691 runtime 12.682 s
1000000000 tested found 228620760 ratio 0.2286208 recursion 2.620 runtime 12.842 s
total 136s = 2m16s (
</pre>
[[user Horst.h|Horst.h]] 06:28, 20 June 2021 (UTC)
== Cheating odd no 5 zumkeller numbers ==
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:I was initially more concerned about my assumption in the isZumkeller() handler logic that odd numbers are always either less than or greater than their aliquot sums, never equal to them. But I've tested up to 9,999,999 this morning and it's held true so far. --[[User:Nig|Nig]] ([[User talk:Nig|talk]]) 11:25, 21 July 2021 (UTC)
::Look for [[Perfect_numbers]] there is a link odd perfect numbers ( > 10^2000 ;-) )
:::The "Odd Perfect" link isn't working, but the Wikipedia entry says: ''"It is unknown whether there is any odd perfect number, though various results have been obtained."'' Numbers beyond 10^2000 are definitely beyond AppleScript's resolution — not to mention that getting to them would take more than the lifetime of the average AppleScript user. So that's a weight off my mind. ;) --[[User:Nig|Nig]] ([[User talk:Nig|talk]]) 13:25, 21 July 2021 (UTC)
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