One-two primes: Difference between revisions

=={{header|J}}==

Implementation:

<syntaxhighlight lang=J>pr12=: {{ for_j. 10x#.1 2{~1|."1#:i.2^y do. if. 1 p:j do. j return. end. end. }}"0</syntaxhighlight>

Task example:

<syntaxhighlight lang=J> ,.pr12 1+i.20

2

11

211

2111

12211

111121

1111211

11221211

111112121

1111111121

11111121121

111111211111

1111111121221

11111111112221

111111112111121

1111111112122111

11111111111112121

111111111111112111

1111111111111111111

11111111111111212121</syntaxhighlight>