wow, very nice, another option that I learn from you!!

nice!

CoffeeScript: Missing random tests

Thanks!

Fixed.

sorry for my importunity, but there's a typo here:
"but depending on seleced method"
-> selected method

I did the same. I like it

added + chai assertions

done

Your solution is almost good, but has a bug, and becomes inaccurate at some point. See following:

Here is row 57 (yours vs expected), which is correct:

Yours:    1, 56, 1540, 27720, 367290, 3819816, 32468436, 231917400, 1420494075, 7575968400, 35607051480, 148902215280, 558383307300, 1889912732400, 5804731963800, 16253249498640, 41648951840265, 97997533741800, 212327989773900, 424655979547800, 785613562163430, 1346766106565880, 2142582442263900, 3167295784216200, 4355031703297275, 5574440580220512, 6646448384109072, 7384942649010080, 7648690600760440, 7384942649010080, [...]
Expected: 1, 56, 1540, 27720, 367290, 3819816, 32468436, 231917400, 1420494075, 7575968400, 35607051480, 148902215280, 558383307300, 1889912732400, 5804731963800, 16253249498640, 41648951840265, 97997533741800, 212327989773900, 424655979547800, 785613562163430, 1346766106565880, 2142582442263900, 3167295784216200, 4355031703297275, 5574440580220512, 6646448384109072, 7384942649010080, 7648690600760440, 7384942649010080, [...]

Here is row 58 (yours vs expected), which starts getting inaccurate:

Yours:    1, 57, 1596, 29260, 395010, 4187106, 36288252, 264385836, 1652411475, 8996462475, 43183019880, 184509266760, 707285522580, 2448296039700, 7694644696200, 22057981462440, 57902201338905, 139646485582065, 310325523515700, 636983969321700, 1210269541711230, 2132379668729310, 3489348548829780, 5309878226480100, 7522327487513475, 9929472283517788, 12220888964329584, 14031391033119152, 15033633249770520, 15033633249770520, 14031391033119152, [...]
Expected: 1, 57, 1596, 29260, 395010, 4187106, 36288252, 264385836, 1652411475, 8996462475, 43183019880, 184509266760, 707285522580, 2448296039700, 7694644696200, 22057981462440, 57902201338905, 139646485582065, 310325523515700, 636983969321700, 1210269541711230, 2132379668729310, 3489348548829780, 5309878226480100, 7522327487513475, 9929472283517787, 12220888964329584, 14031391033119152, 15033633249770520, 15033633249770520, 14031391033119152, [...]

See how your solutions gets 9929472283517788 vs 9929472283517787 incorrectly at row 58. Similarly, all rows beyond 58 contain more and more incorrect numbers. You need to fix a bug in your solution (a very small one!)

What to do if I have reached max buffer size? I have no idea how to solve this in a different way.

should be 7kyu

Lua translation!

it's so easy for me. I'm very happy to improve my logic in javascript with codewars

This kata requires no optimization whatsoever.

Read about properties of prime numbers, filter the possible divisors and their upper-bounds instead of doing an exponential-complexity computation.