Chernick's Carmichael numbers: Difference between revisions

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 * [https://oeis.org/A318646 OEIS A318646: The least Chernick's "universal form" Carmichael number with n prime factors]
+=={{header|Go}}==
+<lang go>package main
+import (
+    "fmt"
+    "math/big"
+)
+var (
+    zero = new(big.Int)
+    prod = new(big.Int)
+    fact = new(big.Int)
+)
+func ccFactors(n, m uint64) (*big.Int, bool) {
+    prod.SetUint64(6*m + 1)
+    if !prod.ProbablyPrime(10) {
+        return zero, false
+    }
+    fact.SetUint64(12*m + 1)
+    if !fact.ProbablyPrime(10) {
+        return zero, false
+    }
+    prod.Mul(prod, fact)
+    for i := uint64(1); i <= n-2; i++ {
+        fact.SetUint64((1<<i)*9*m + 1)
+        if !fact.ProbablyPrime(10) {
+            return zero, false
+        }
+        prod.Mul(prod, fact)
+    }
+    return prod, true
+}
+func ccNumbers(start, end uint64) {
+    for n := start; n <= end; n++ {
+        m := uint64(1)
+        if n > 4 {
+            m = 1 << (n - 4)
+        }
+        for {
+            num, ok := ccFactors(n, m)
+            if ok {
+                fmt.Printf("a(%d) = %d\n", n, num)
+                break
+            }
+            if n <= 4 {
+                m++
+            } else {
+                m += 1 << (n - 4)
+            }
+        }
+    }
+}
+func main() {
+    ccNumbers(3, 9)
+}</lang>
+{{out}}
+<pre>
+a(3) = 1729
+a(4) = 63973
+a(5) = 26641259752490421121
+a(6) = 1457836374916028334162241
+a(7) = 24541683183872873851606952966798288052977151461406721
+a(8) = 53487697914261966820654105730041031613370337776541835775672321
+a(9) = 58571442634534443082821160508299574798027946748324125518533225605795841
+</pre>
 =={{header|Perl}}==