Frobenius numbers: Difference between revisions

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=={{header|jq}}==

{{works with|jq}}

'''Works with gojq, the Go implementation of jq'''

The solution offered here is based on a function that can generate an unbounded stream of Frobenius numbers without relying on the precomputation or storage of an array of primes except as may be used by `is_prime`.

See e.g. [[Erd%C5%91s-primes#jq]] for a suitable implementation of `is_prime`.

<lang jq># Generate a stream of Frobenius numbers up to an including `.`;

# specify `null` or `infinite` to generate an unbounded stream.

def frobenius:

. as $limit

| label $out

| foreach (range(3;infinite;2) | select(is_prime)) as $p ({p: null, prev: 2};

.p = $p

| (.prev * $p - .prev - $p) as $frob

| if $limit == null or $frob > $limit then break $out

else .frob = $frob

end

| .prev = $p;

.frob);

10001 | frobenius</lang>

{{out}}

<pre>

1

7

23

59

119

191

287

395

615

839

1079

1439

1679

1931

2391

3015

3479

3959

4619

5039

5615

6395

7215

8447

9599