Duffinian numbers: Difference between revisions
Added Go
Drkameleon (talk | contribs) |
(Added Go) |
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6399 6400 6401
8449 8450 8451
</pre>
=={{header|Go}}==
{{trans|Wren}}
{{libheader|Go-rcu}}
<lang go>package main
import (
"fmt"
"math"
"rcu"
)
func isSquare(n int) bool {
s := int(math.Sqrt(float64(n)))
return s*s == n
}
func main() {
limit := 200000 // say
d := rcu.PrimeSieve(limit-1, true)
d[1] = false
for i := 2; i < limit; i++ {
if !d[i] {
continue
}
if i%2 == 0 && !isSquare(i) && !isSquare(i/2) {
d[i] = false
continue
}
sigmaSum := rcu.SumInts(rcu.Divisors(i))
if rcu.Gcd(sigmaSum, i) != 1 {
d[i] = false
}
}
var duff []int
for i := 1; i < len(d); i++ {
if d[i] {
duff = append(duff, i)
}
}
fmt.Println("First 50 Duffinian numbers:")
rcu.PrintTable(duff[0:50], 10, 3, false)
var triplets [][3]int
for i := 2; i < limit; i++ {
if d[i] && d[i-1] && d[i-2] {
triplets = append(triplets, [3]int{i - 2, i - 1, i})
}
}
fmt.Println("\nFirst 56 Duffinian triplets:")
for i := 0; i < 14; i++ {
s := fmt.Sprintf("%6v", triplets[i*4:i*4+4])
fmt.Println(s[1 : len(s)-1])
}
}</lang>
{{out}}
<pre>
First 50 Duffinian numbers:
4 8 9 16 21 25 27 32 35 36
39 49 50 55 57 63 64 65 75 77
81 85 93 98 100 111 115 119 121 125
128 129 133 143 144 155 161 169 171 175
183 185 187 189 201 203 205 209 215 217
First 56 Duffinian triplets:
[ 63 64 65] [ 323 324 325] [ 511 512 513] [ 721 722 723]
[ 899 900 901] [ 1443 1444 1445] [ 2303 2304 2305] [ 2449 2450 2451]
[ 3599 3600 3601] [ 3871 3872 3873] [ 5183 5184 5185] [ 5617 5618 5619]
[ 6049 6050 6051] [ 6399 6400 6401] [ 8449 8450 8451] [ 10081 10082 10083]
[ 10403 10404 10405] [ 11663 11664 11665] [ 12481 12482 12483] [ 13447 13448 13449]
[ 13777 13778 13779] [ 15841 15842 15843] [ 17423 17424 17425] [ 19043 19044 19045]
[ 26911 26912 26913] [ 30275 30276 30277] [ 36863 36864 36865] [ 42631 42632 42633]
[ 46655 46656 46657] [ 47523 47524 47525] [ 53137 53138 53139] [ 58563 58564 58565]
[ 72961 72962 72963] [ 76175 76176 76177] [ 79523 79524 79525] [ 84099 84100 84101]
[ 86527 86528 86529] [ 94177 94178 94179] [108899 108900 108901] [121103 121104 121105]
[125315 125316 125317] [128017 128018 128019] [129599 129600 129601] [137287 137288 137289]
[144399 144400 144401] [144721 144722 144723] [154567 154568 154569] [158403 158404 158405]
[166463 166464 166465] [167041 167042 167043] [175231 175232 175233] [177607 177608 177609]
[181475 181476 181477] [186623 186624 186625] [188497 188498 188499] [197191 197192 197193]
</pre>
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