Forbidden numbers: Difference between revisions
Added Go
(→{{header|Python}}: prepend Pascal version calculating count extreme fast.) |
(Added Go) |
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;* [[oeis:A004215|OEIS A004215 - Numbers that are the sum of 4 but no fewer nonzero squares]]
=={{header|Go}}==
{{libheader|Go-rcu}}
A translation of the Python code in the OEIS link. Runtime around 7 seconds.
<syntaxhighlight lang="go">package main
import (
"fmt"
"math"
"rcu"
)
func isForbidden(n int) bool {
m := n
v := 0
for m > 1 && m%4 == 0 {
m /= 4
v++
}
pow := int(math.Pow(4, float64(v)))
return n/pow%8 == 7
}
func main() {
forbidden := make([]int, 50)
for i, count := 0, 0; count < 50; i++ {
if isForbidden(i) {
forbidden[count] = i
count++
}
}
fmt.Println("The first 50 forbidden numbers are:")
rcu.PrintTable(forbidden, 10, 3, false)
fmt.Println()
limit := 500
count := 0
for i := 1; ; i++ {
if isForbidden(i) {
count++
}
if i == limit {
slimit := rcu.Commatize(limit)
scount := rcu.Commatize(count)
fmt.Printf("Forbidden number count <= %11s: %10s\n", slimit, scount)
if limit == 500_000_000 {
return
}
limit *= 10
}
}
}</syntaxhighlight>
{{out}}
<pre>
The first 50 forbidden numbers are:
7 15 23 28 31 39 47 55 60 63
71 79 87 92 95 103 111 112 119 124
127 135 143 151 156 159 167 175 183 188
191 199 207 215 220 223 231 239 240 247
252 255 263 271 279 284 287 295 303 311
Forbidden number count <= 500: 82
Forbidden number count <= 5,000: 831
Forbidden number count <= 50,000: 8,330
Forbidden number count <= 500,000: 83,331
Forbidden number count <= 5,000,000: 833,329
Forbidden number count <= 50,000,000: 8,333,330
Forbidden number count <= 500,000,000: 83,333,328
</pre>
=={{header|jq}}==
Line 87 ⟶ 156:
Forbidden number count up to 500000: 83331
</pre>
=={{header|Pascal}}==
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