Cullen and Woodall numbers: Difference between revisions

</pre>

=={{header|Go}}==

{{libheader|GMP(Go wrapper)}}

<lang go>package main

import (

"fmt"

big "github.com/ncw/gmp"

)

func cullen(n uint) *big.Int {

one := big.NewInt(1)

bn := big.NewInt(int64(n))

res := new(big.Int).Lsh(one, n)

res.Mul(res, bn)

return res.Add(res, one)

}

func woodall(n uint) *big.Int {

res := cullen(n)

return res.Sub(res, big.NewInt(2))

}

func main() {

fmt.Println("First 20 Cullen numbers (n * 2^n + 1):")

for n := uint(1); n <= 20; n++ {

fmt.Printf("%d ", cullen(n))

}

fmt.Println("\n\nFirst 20 Woodall numbers (n * 2^n - 1):")

for n := uint(1); n <= 20; n++ {

fmt.Printf("%d ", woodall(n))

}

fmt.Println("\n\nFirst 5 Cullen primes (in terms of n):")

count := 0

for n := uint(1); count < 5; n++ {

cn := cullen(n)

if cn.ProbablyPrime(15) {

fmt.Printf("%d ", n)

count++

}

}

fmt.Println("\n\nFirst 12 Woodall primes (in terms of n):")

count = 0

for n := uint(1); count < 12; n++ {

cn := woodall(n)

if cn.ProbablyPrime(15) {

fmt.Printf("%d ", n)

count++

}

}

fmt.Println()

}</lang>

{{out}}

<pre>

First 20 Cullen numbers (n * 2^n + 1):

3 9 25 65 161 385 897 2049 4609 10241 22529 49153 106497 229377 491521 1048577 2228225 4718593 9961473 20971521

First 20 Woodall numbers (n * 2^n - 1):

1 7 23 63 159 383 895 2047 4607 10239 22527 49151 106495 229375 491519 1048575 2228223 4718591 9961471 20971519

First 5 Cullen primes (in terms of n):

1 141 4713 5795 6611

First 12 Woodall primes (in terms of n):

2 3 6 30 75 81 115 123 249 362 384 462