Repunits are numbers that consist entirely of repetitions of the digit one (unity). The notation Rn symbolizes the repunit made up of n ones.

Every prime p larger than 5, evenly divides the repunit Rp-1.



E.G.
The repunit R6 is evenly divisible by 7.

111111 / 7 = 15873

The repunit R42 is evenly divisible by 43.

111111111111111111111111111111111111111111 / 43 = 2583979328165374677002583979328165374677

And so on.



There are composite numbers that also have this same property. They are often referred to as deceptive non-primes or deceptive numbers.



The repunit R90 is evenly divisible by the composite number 91 (=7*13).

111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111 / 91 = 1221001221001221001221001221001221001221001221001221001221001221001221001221001221001221


Task 
 Find and show at least the first 10 deceptive numbers; composite numbers n that evenly divide the repunit Rn-1


See also
 Numbers Aplenty - Deceptive numbers
 OEIS:A000864 - Deceptive nonprimes: composite numbers k that divide the repunit R_{k-1}




package main
 
import (
    "fmt"
    "math/big"
    "rcu"
)
 
func main() {
    count := 0
    limit := 25
    n := int64(17)
    repunit := big.NewInt(1111111111111111)
    t := new(big.Int)
    zero := new(big.Int)
    eleven := big.NewInt(11)
    hundred := big.NewInt(100)
    var deceptive []int64
    for count < limit {
        if !rcu.IsPrime(int(n)) && n%3 != 0 && n%5 != 0 {
            bn := big.NewInt(n)
            if t.Rem(repunit, bn).Cmp(zero) == 0 {
                deceptive = append(deceptive, n)
                count++
            }
        }
        n += 2
        repunit.Mul(repunit, hundred)
        repunit.Add(repunit, eleven)
    }
    fmt.Println("The first", limit, "deceptive numbers are:")
    fmt.Println(deceptive)
}