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let rec fG n g=if g<10 then i[g]<-n i[g] 1 else i[g%10]<-n i[g%10] 1; fG n (g/10)
fG (+) n; fG (-) g; Array.forall ((=)0) i
primes32()let oPairs n=n|>Seq.pairwise|>Seq.filter fG|>Seq.take 30|>Seq.iter(printf "%A "); printfn ""
printfn $"<1 million: %d{primes32()|>Seq.takeWhile((>)1000000)oPairs|>Seq.pairwisetake 30|>Seq.filteriter(printf fG|>Seq.length}"%A "); printfn ""
printfn $"<101 million: %d{primes32()|>Seq.takeWhile((>)100000001000000)|>Seq.pairwise|>Seq.filter fGoPairs|>Seq.length}"
printfn $"<10010 million: %d{primes32()|>Seq.takeWhile((>)10000000010000000)|>Seq.pairwise|>Seq.filter fGoPairs|>Seq.length}"
printfn $"<1100 billionmillion: %d{primes32()|>Seq.takeWhile((>)1000000000100000000)|>Seq.pairwise|>Seq.filter fGoPairs|>Seq.length}"
printfn $"<1 billion: %d{primes32()|>Seq.takeWhile((>)1000000000)|>oPairs|>Seq.length}"
</syntaxhighlight>
{{out}}
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