Successive prime differences: Difference between revisions
Added 11l
Alextretyak (talk | contribs) (Added 11l) |
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:#https://www.primepuzzles.net/puzzles/puzz_011.htm
:#https://matheplanet.de/matheplanet/nuke/html/viewtopic.php?topic=232720&start=0
=={{header|11l}}==
{{trans|D}}
<lang 11l>F primes_upto(limit)
V is_prime = [0B] * 2 [+] [1B] * (limit - 1)
L(n) 0 .< Int(limit ^ 0.5 + 1.5)
I is_prime[n]
L(i) (n * n .< limit + 1).step(n)
is_prime[i] = 0B
R enumerate(is_prime).filter((i, prime) -> prime).map((i, prime) -> i)
F successive_primes(primes, diffs)
[[Int]] results
V dl = diffs.len
L(i) 0 .< primes.len - dl
V group = [0] * (dl + 1)
group[0] = primes[i]
L(j) i .+ dl
I primes[j + 1] - primes[j] != diffs[j - i]
L.break
group[j - i + 1] = primes[j + 1]
L.was_no_break
results [+]= group
R results
V prime_list = primes_upto(1'000'000)
print(‘For primes less than 1,000,000:-’)
L(diffs) [[2], [1], [2, 2], [2, 4], [4, 2], [6, 4, 2]]
print(‘ For differences of #. ->’.format(diffs))
V sp = successive_primes(prime_list, diffs)
print(‘ First group = ’sp[0])
print(‘ Last group = ’sp.last)
print(‘ Number found = ’sp.len)
print()</lang>
{{out}}
<pre>
For primes less than 1,000,000:-
For differences of [2] ->
First group = [3, 5]
Last group = [999959, 999961]
Number found = 8169
For differences of [1] ->
First group = [2, 3]
Last group = [2, 3]
Number found = 1
For differences of [2, 2] ->
First group = [3, 5, 7]
Last group = [3, 5, 7]
Number found = 1
For differences of [2, 4] ->
First group = [5, 7, 11]
Last group = [999431, 999433, 999437]
Number found = 1393
For differences of [4, 2] ->
First group = [7, 11, 13]
Last group = [997807, 997811, 997813]
Number found = 1444
For differences of [6, 4, 2] ->
First group = [31, 37, 41, 43]
Last group = [997141, 997147, 997151, 997153]
Number found = 306
</pre>
=={{header|ALGOL 68}}==
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