Blum integer: Difference between revisions
Add Scala implementation
(→{{header|Perl}}: much faster code: use factor() from ntheory, instead of pure-perl Pollard rho) |
(Add Scala implementation) |
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26828th Blum number: 524273
</pre>
=={{header|Scala}}==
{{trans|Java}}
<syntaxhighlight lang="Scala">
import scala.collection.mutable
object BlumInteger extends App {
var blums = new Array[Int](50)
var blumCount = 0
val lastDigitCounts = mutable.Map[Int, Int]()
var number = 1
while (blumCount < 400_000) {
val prime = leastPrimeFactor(number)
if (prime % 4 == 3) {
val quotient = number / prime
if (quotient != prime && isPrimeType3(quotient)) {
if (blumCount < 50) {
blums(blumCount) = number
}
lastDigitCounts(number % 10) = lastDigitCounts.getOrElse(number % 10, 0) + 1
blumCount += 1
if (blumCount == 50) {
println("The first 50 Blum integers:")
blums.grouped(10).foreach(group => println(group.map(i => f"$i%3d").mkString(" ")))
println("")
} else if (blumCount == 26828 || blumCount % 100_000 == 0) {
println(f"The ${blumCount}th Blum integer is: $number%7d")
if (blumCount == 400_000) {
println("\nPercent distribution of the first 400000 Blum integers:")
lastDigitCounts.foreach { case (key, count) =>
println(f" ${count.toDouble / 4000}%6.3f%% end in $key")
}
}
}
}
}
number += (if (number % 5 == 3) 4 else 2)
}
def isPrimeType3(aNumber: Int): Boolean = {
if (aNumber < 2) return false
if (aNumber % 2 == 0) return aNumber == 2
if (aNumber % 3 == 0) return aNumber == 3
var divisor = 5
while (divisor * divisor <= aNumber) {
if (aNumber % divisor == 0) return false
divisor += 2
}
aNumber % 4 == 3
}
def leastPrimeFactor(aNumber: Int): Int = {
if (aNumber == 1) return 1
if (aNumber % 2 == 0) return 2
if (aNumber % 3 == 0) return 3
var divisor = 5
while (divisor * divisor <= aNumber) {
if (aNumber % divisor == 0) return divisor
divisor += 2
}
aNumber
}
}
</syntaxhighlight>
{{out}}
<pre>
The first 50 Blum integers:
21 33 57 69 77 93 129 133 141 161
177 201 209 213 217 237 249 253 301 309
321 329 341 381 393 413 417 437 453 469
473 489 497 501 517 537 553 573 581 589
597 633 649 669 681 713 717 721 737 749
The 26828th Blum integer is: 524273
The 100000th Blum integer is: 2075217
The 200000th Blum integer is: 4275533
The 300000th Blum integer is: 6521629
The 400000th Blum integer is: 8802377
Percent distribution of the first 400000 Blum integers:
25.001% end in 1
25.017% end in 3
24.997% end in 7
24.985% end in 9
</pre>
=={{header|Sidef}}==
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