Data commit

Task/Smarandache-prime-digital-sequence/Go/smarandache-prime-digital-sequence-1.go

@@ -0,0 +1,54 @@
+package main
+
+import (
+    "fmt"
+    "math/big"
+)
+
+var b = new(big.Int)
+
+func isSPDSPrime(n uint64) bool {
+    nn := n
+    for nn > 0 {
+        r := nn % 10
+        if r != 2 && r != 3 && r != 5 && r != 7 {
+            return false
+        }
+        nn /= 10
+    }
+    b.SetUint64(n)
+    if b.ProbablyPrime(0) { // 100% accurate up to 2 ^ 64
+        return true
+    }
+    return false
+}
+
+func listSPDSPrimes(startFrom, countFrom, countTo uint64, printOne bool) uint64 {
+    count := countFrom
+    for n := startFrom; ; n += 2 {
+        if isSPDSPrime(n) {
+            count++
+            if !printOne {
+                fmt.Printf("%2d. %d\n", count, n)
+            }
+            if count == countTo {
+                if printOne {
+                    fmt.Println(n)
+                }
+                return n
+            }
+        }
+    }
+}
+
+func main() {
+    fmt.Println("The first 25 terms of the Smarandache prime-digital sequence are:")
+    fmt.Println(" 1. 2")
+    n := listSPDSPrimes(3, 1, 25, false)
+    fmt.Println("\nHigher terms:")
+    indices := []uint64{25, 100, 200, 500, 1000, 2000, 5000, 10000, 20000, 50000, 100000}
+    for i := 1; i < len(indices); i++ {
+        fmt.Printf("%6d. ", indices[i])
+        n = listSPDSPrimes(n+2, indices[i-1], indices[i], true)
+    }
+}

Task/Smarandache-prime-digital-sequence/Go/smarandache-prime-digital-sequence-2.go

@@ -0,0 +1,88 @@
+package main
+
+import (
+    "fmt"
+    "math/big"
+)
+
+type B2357 []byte
+
+var bi = new(big.Int)
+
+func isSPDSPrime(b B2357) bool {
+    bi.SetString(string(b), 10)
+    return bi.ProbablyPrime(0) // 100% accurate up to 2 ^ 64
+}
+
+func listSPDSPrimes(startFrom B2357, countFrom, countTo uint64, printOne bool) B2357 {
+    count := countFrom
+    n := startFrom
+    for {
+        if isSPDSPrime(n) {
+            count++
+            if !printOne {
+                fmt.Printf("%2d. %s\n", count, string(n))
+            }
+            if count == countTo {
+                if printOne {
+                    fmt.Println(string(n))
+                }
+                return n
+            }
+        }
+        if printOne {
+            n = n.AddTwo()
+        } else {
+            n = n.AddOne()
+        }
+    }
+}
+
+func incDigit(digit byte) byte {
+    switch digit {
+    case '2':
+        return '3'
+    case '3':
+        return '5'
+    case '5':
+        return '7'
+    default:
+        return '9' // say
+    }
+}
+
+func (b B2357) AddOne() B2357 {
+    le := len(b)
+    b[le-1] = incDigit(b[le-1])
+    for i := le - 1; i >= 0; i-- {
+        if b[i] < '9' {
+            break
+        } else if i > 0 {
+            b[i] = '2'
+            b[i-1] = incDigit(b[i-1])
+        } else {
+            b[0] = '2'
+            nb := make(B2357, le+1)
+            copy(nb[1:], b)
+            nb[0] = '2'
+            return nb
+        }
+    }
+    return b
+}
+
+func (b B2357) AddTwo() B2357 {
+    return b.AddOne().AddOne()
+}
+
+func main() {
+    fmt.Println("The first 25 terms of the Smarandache prime-digital sequence are:")
+    n := listSPDSPrimes(B2357{'2'}, 0, 4, false)
+    n = listSPDSPrimes(n.AddOne(), 4, 25, false)
+    fmt.Println("\nHigher terms:")
+    indices := []uint64{25, 100, 200, 500, 1000, 2000, 5000, 10000, 20000, 50000, 100000}
+    for i := 1; i < len(indices); i++ {
+        fmt.Printf("%6d. ", indices[i])
+        n = listSPDSPrimes(n.AddTwo(), indices[i-1], indices[i], true)
+    }
+}