Concatenate two primes is also prime: Difference between revisions
Concatenate two primes is also prime (view source)
Revision as of 01:37, 6 December 2021
, 2 years agoConcatenate two primes is also prime en Yabasic
(Ada version) |
(Concatenate two primes is also prime en Yabasic) |
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</pre>
=={{header|
{{works with|Factor|0.99 2021-06-02}}▼
<lang factor>USING: formatting grouping io kernel math.parser math.primes▼
present prettyprint sequences sets sorting ;▼
==={{header|FreeBASIC}}===▼
"Concatenated-pair primes from primes < 100:" print nl▼
99 primes-upto [ present ] map dup [ append dec> ] cartesian-map▼
concat [ prime? ] filter members natural-sort [ length ] keep▼
8 group simple-table. "\nFound %d concatenated primes.\n" printf</lang>▼
{{out}}▼
<pre>▼
Concatenated-pair primes from primes < 100:▼
23 37 53 73 113 137 173 193▼
197 211 223 229 233 241 271 283▼
293 311 313 317 331 337 347 353▼
359 367 373 379 383 389 397 433▼
523 541 547 571 593 613 617 673▼
677 719 733 743 761 773 797 977▼
1117 1123 1129 1153 1171 1319 1361 1367▼
1373 1723 1741 1747 1753 1759 1783 1789▼
1913 1931 1973 1979 1997 2311 2341 2347▼
2371 2383 2389 2917 2953 2971 3119 3137▼
3167 3719 3761 3767 3779 3797 4111 4129▼
4153 4159 4337 4373 4397 4723 4729 4759▼
4783 4789 5323 5347 5923 5953 6113 6131▼
6143 6173 6197 6719 6737 6761 6779 7129▼
7159 7331 7919 7937 8311 8317 8329 8353▼
8389 8923 8929 8941 8971 9719 9743 9767▼
Found 128 concatenated primes.▼
</pre>▼
▲=={{header|FreeBASIC}}==
This solution focuses more on the primes p1, p2 than on the concatenated prime. Thus, there can be multiple solutions. For example, 373 can be formed from 37 and 3 or from 3 and 73 and will be listed twice.
<lang freebasic>#include "isprime.bas"
Line 379 ⟶ 348:
83|17 83|29 83|53 83|89 89|23 89|29 89|41 89|71 97| 7 97|19
97|43 97|67
▲</pre>
==={{header|Yabasic}}===
<lang yabasic>c = 0
for p1 = 2 to 99
if not isPrime(p1) then continue : fi
for p2 = 2 to 99
if not isPrime(p2) then continue : fi
cat = val(str$(p1) + str$(p2))
if isPrime(cat) then
c = c + 1
a$ = str$(p1,"##")
b$ = str$(p2,"##")
print a$, "|", b$, " ";
if mod(c, 10) = 0 then print : fi
end if
next p2
next p1
print
end
sub isPrime(v)
if v < 2 then return False : fi
if mod(v, 2) = 0 then return v = 2 : fi
if mod(v, 3) = 0 then return v = 3 : fi
d = 5
while d * d <= v
if mod(v, d) = 0 then return False else d = d + 2 : fi
wend
return True
end sub</lang>
=={{header|Factor}}==
▲{{works with|Factor|0.99 2021-06-02}}
▲<lang factor>USING: formatting grouping io kernel math.parser math.primes
▲present prettyprint sequences sets sorting ;
▲"Concatenated-pair primes from primes < 100:" print nl
▲99 primes-upto [ present ] map dup [ append dec> ] cartesian-map
▲concat [ prime? ] filter members natural-sort [ length ] keep
▲8 group simple-table. "\nFound %d concatenated primes.\n" printf</lang>
▲{{out}}
▲<pre>
▲Concatenated-pair primes from primes < 100:
▲23 37 53 73 113 137 173 193
▲197 211 223 229 233 241 271 283
▲293 311 313 317 331 337 347 353
▲359 367 373 379 383 389 397 433
▲523 541 547 571 593 613 617 673
▲677 719 733 743 761 773 797 977
▲1117 1123 1129 1153 1171 1319 1361 1367
▲1373 1723 1741 1747 1753 1759 1783 1789
▲1913 1931 1973 1979 1997 2311 2341 2347
▲2371 2383 2389 2917 2953 2971 3119 3137
▲3167 3719 3761 3767 3779 3797 4111 4129
▲4153 4159 4337 4373 4397 4723 4729 4759
▲4783 4789 5323 5347 5923 5953 6113 6131
▲6143 6173 6197 6719 6737 6761 6779 7129
▲7159 7331 7919 7937 8311 8317 8329 8353
▲8389 8923 8929 8941 8971 9719 9743 9767
▲Found 128 concatenated primes.
</pre>
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