Consecutive primes with ascending or descending differences: Difference between revisions
Consecutive primes with ascending or descending differences (view source)
Revision as of 16:52, 12 June 2021
, 2 years agoAdded Go
m (added to Prime Numbers category.) |
(Added Go) |
||
Line 404:
The longest sequence of descending primes (with their difference from the last one) is:
322171 (22) 322193 (20) 322213 (16) 322229 (8) 322237 (6) 322243 (4) 322247 (2) 322249</pre>
=={{header|Go}}==
{{trans|Wren}}
<lang go>package main
import (
"fmt"
"rcu"
)
const LIMIT = 999999
var primes = rcu.Primes(LIMIT)
func longestSeq(dir string) {
pd := 0
longSeqs := [][]int{{2}}
currSeq := []int{2}
for i := 1; i < len(primes); i++ {
d := primes[i] - primes[i-1]
if (dir == "ascending" && d <= pd) || (dir == "descending" && d >= pd) {
if len(currSeq) > len(longSeqs[0]) {
longSeqs = [][]int{currSeq}
} else if len(currSeq) == len(longSeqs[0]) {
longSeqs = append(longSeqs, currSeq)
}
currSeq = []int{primes[i-1], primes[i]}
} else {
currSeq = append(currSeq, primes[i])
}
pd = d
}
if len(currSeq) > len(longSeqs[0]) {
longSeqs = [][]int{currSeq}
} else if len(currSeq) == len(longSeqs[0]) {
longSeqs = append(longSeqs, currSeq)
}
fmt.Println("Longest run(s) of primes with", dir, "differences is", len(longSeqs[0]), ":")
for _, ls := range longSeqs {
var diffs []int
for i := 1; i < len(ls); i++ {
diffs = append(diffs, ls[i]-ls[i-1])
}
for i := 0; i < len(ls)-1; i++ {
fmt.Print(ls[i], " (", diffs[i], ") ")
}
fmt.Println(ls[len(ls)-1])
}
fmt.Println()
}
func main() {
fmt.Println("For primes < 1 million:\n")
for _, dir := range []string{"ascending", "descending"} {
longestSeq(dir)
}
}</lang>
{{out}}
<pre>
For primes < 1 million:
Longest run(s) of primes with ascending differences is 8 :
128981 (2) 128983 (4) 128987 (6) 128993 (8) 129001 (10) 129011 (12) 129023 (14) 129037
402581 (2) 402583 (4) 402587 (6) 402593 (8) 402601 (12) 402613 (18) 402631 (60) 402691
665111 (2) 665113 (4) 665117 (6) 665123 (8) 665131 (10) 665141 (12) 665153 (24) 665177
Longest run(s) of primes with descending differences is 8 :
322171 (22) 322193 (20) 322213 (16) 322229 (8) 322237 (6) 322243 (4) 322247 (2) 322249
752207 (44) 752251 (12) 752263 (10) 752273 (8) 752281 (6) 752287 (4) 752291 (2) 752293
</pre>
=={{header|Julia}}==
| |||