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- #!/usr/bin/ruby
- # 3-powerful numbers that can be written as the sum of two coprime 3-powerful numbers.
- # https://oeis.org/A297867
- #var n = 11205183603973252067
- var n = 3518958160000
- var t = n.rad
- n.powerful(3).each {|k|
- k.is_coprime(t) || next
- if (n - k -> is_powerful(3)) {
- say "#{n} = #{k} + #{n-k}"
- break
- }
- }
- __END__
- 776151559 = 756249048 + 19902511
- 3518958160000 = 1392672604221 + 2126285555779
- 11205183603973252067 = 5317378991792784000 + 5887804612180468067
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