Talk:Untouchable numbers: Difference between revisions
New section about faster proper divisor sum calculation.
(New section about faster proper divisor sum calculation.) |
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Rule 2 is applied when the prime changes: i<-new prime; Π<-Π*i; g<-e*g; e<-1+i; and l<-i*i.
--[[User:Nigel Galloway|Nigel Galloway]] ([[User talk:Nigel Galloway|talk]]) 13:21, 9 March 2021 (UTC)
==Faster Proper Divisor Sum calculation==
The Algol 68 solution uses a sieve rather than modulo operations to construct a table of proper divisor sums.
Using an experimental, home-grown transpiler to VB.NET and running under .Net Framework 3.5 on a Windows 7 machine, it calculated the number of untouchables up to 1 million in less than a minute (about 40 seconds) - as with the Go etc. samples a sieve factor of 64 is used.
I don't claim the generated VB.NET is anything special, BTW.
--[[User:Tigerofdarkness|Tigerofdarkness]] ([[User talk:Tigerofdarkness|talk]]) 18:58, 28 June 2021 (UTC)
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