package main
import "fmt"
import "libs/sieve"
const max = 1000000
var s = sieve.MakeSieve(max)
func countDigits(n int) int {
digits := 0
for ; n > 0; n /= 10 {
digits += 1
}
return digits
}
func rotate(n int, digits int) int {
p := n % 10
for ; digits > 1; digits-- {
p *= 10
}
return p + (n / 10)
}
func checkCircularPrime(n int) bool {
digits := countDigits(n)
for d := digits; d > 0; d-- {
n = rotate(n, digits)
if !s.IsPrime(int64(n)) {
return false
package main
import "fmt"
import "libs/sieve"
var s *sieve.Sieve = sieve.MakeSieve(10000)
func consecutivePrimes(a, b int64) int {
var i int64
for i = 1; s.IsPrime(i*i + a*i + b); i++ {
}
return int(i)
}
func main() {
maxA, maxB, maxCount := int64(0), int64(0), 0
for b := int64(0); b < 1000; b++ {
if s.IsPrime(b) {
for a := int64(-999); a < 1000; a++ {
count := consecutivePrimes(a, b)
if count > maxCount {
maxA, maxB, maxCount = a, b, count
}
}
}
}
fmt.Println(maxA, maxB, maxCount, maxA*maxB)
//fmt.Println(1,41,consecutivePrimes(1,41))
//fmt.Println(-79,1601,consecutivePrimes(-79,1601))
package main
import "fmt"
import "libs/sieve"
const n = 10000
var s = sieve.MakeSieve(n)
type FactorTableEntry struct{ factor, remainder int }
type FactorTable []FactorTableEntry
var tab = make(FactorTable, n)
func computePropDivisors(i int) map[int]bool {
if i == 1 {
return map[int]bool{1: true}
} else {
fact := tab[i].factor
rem := tab[i].remainder
rv := computePropDivisors(rem)
additions := make([]int, len(rv))
j := 0
for f, _ := range rv {
additions[j] = f * fact
j++
}
for _, f := range additions {
rv[f] = true
}
return rv
