A367647 Irregular triangle read by rows in which row n lists the positive values k such that there are no primes between k*n and k*(n + 1), or -1 if no such k exists.

1, 1, 2, 1, 4, 2, 1, 3, 4, 1, 2, 3, 2, 4, 2, 9, 1, 1, 6, 2, 3, 2, 7, 3, 5, 2, 6, 1, 6, 7, 10, 1, 3, 4, 2, 4, 5, 1, 2, 5, 1, 2, 3, 8, 1, 7, 1, 2, 2, 3, 5, 4, 7, 11, 3, 4, 2, 3, 1, 2, 10, 1, 4, 9, 1, 2, 6, 1, 4, 15, 4, 6, 2, 5, 8, 1, 2, 3, 4, 1, 3, 2, 3, 5, 8, 3, 5, 2, 4, 7, 2, 5, 1, 3, 12, 1, 2, 2, 4, 7

Offset

1,3

Links

Table of n, a(n) for n=1..100.

Example

Triangle begins:
1;
1;
1;
2;
1;
4;
2;
1, 3, 4;
1;
2;
3;
2, 4;
2, 9;
1;
1, 6;
2, 3;
2, 7;
3, 5;
2, 6;
1, 6, 7, 10;
1, 3, 4;
2;
4, 5;
1, 2, 5;
1, 2, 3, 8.

Crossrefs

Cf. A068780, A047845, A110835, A278425.

Sequence in context: A268267 A378198 A205395 * A243070 A243060 A286321

Adjacent sequences: A367644 A367645 A367646 * A367648 A367649 A367650

Keyword

nonn,tabf,easy

Author

Juri-Stepan Gerasimov, Nov 25 2023

Status

approved