Jacobsthal numbers: Difference between revisions
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313 5562466239377370006237035693149875298444543026970449921737087520370363869220418099018130434731
347 95562442332919646317117537304253622533190207882011713489066201641121786503686867002917439712921903606443</pre>
=={{header|OCaml}}==
<syntaxhighlight lang="ocaml">let is_prime n =
let rec test x =
x * x > n || n mod x <> 0 && n mod (x + 2) <> 0 && test (x + 6)
in
if n < 5
then n land 2 <> 0
else n land 1 <> 0 && n mod 3 <> 0 && test 5
let seq_jacobsthal =
let rec next b a () = Seq.Cons (a, next (a + a + b) b) in
next 1
let seq_jacobsthal_oblong =
let rec next b a () = Seq.Cons (a * b, next (a + a + b) b) in
next 1 0
let () =
let show (n, seq, s) =
Seq.take n seq
|> Seq.fold_left (Printf.sprintf "%s %u") (Printf.sprintf "First %u %s numbers:\n" n s)
|> print_endline
in
List.iter show [
30, seq_jacobsthal 0, "Jacobsthal";
30, seq_jacobsthal 2, "Jacobsthal-Lucas";
20, seq_jacobsthal_oblong, "Jacobsthal oblong";
10, Seq.filter is_prime (seq_jacobsthal 0), "Jacobsthal prime"]</syntaxhighlight>
{{out}}
<pre>
First 30 Jacobsthal numbers:
0 1 1 3 5 11 21 43 85 171 341 683 1365 2731 5461 10923 21845 43691 87381 174763 349525 699051 1398101 2796203 5592405 11184811 22369621 44739243 89478485 178956971
First 30 Jacobsthal-Lucas numbers:
2 1 5 7 17 31 65 127 257 511 1025 2047 4097 8191 16385 32767 65537 131071 262145 524287 1048577 2097151 4194305 8388607 16777217 33554431 67108865 134217727 268435457 536870911
First 20 Jacobsthal oblong numbers:
0 1 3 15 55 231 903 3655 14535 58311 232903 932295 3727815 14913991 59650503 238612935 954429895 3817763271 15270965703 61084037575
First 10 Jacobsthal prime numbers:
3 5 11 43 683 2731 43691 174763 2796203 715827883
</pre>
=={{header|Perl}}==
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