A231353 Least k>=0 such that n - k^2 is a triangular number, or -1 if no such k exists.

0, 0, 1, 0, 1, 2, 0, 1, -1, 3, 0, 1, 3, -1, 2, 0, 1, 4, -1, 2, -1, 0, 1, -1, 3, 2, 4, -1, 0, 1, 3, 4, 2, -1, -1, 5, 0, 1, -1, 6, 2, -1, 6, -1, 4, 0, 1, -1, -1, 2, 7, 6, 4, 5, 3, 0, 1, 6, -1, 2, -1, 4, -1, -1, 3, 8, 0, 1, -1, -1, 2, 4, 6, -1, 8, 3, -1, 7, 0, 1, 5, 6, 2

Offset

0,6

Comments

Indices of -1's: A014134.

Indices of 0's: A000217.

Indices of 1's: A000124.

Links

Table of n, a(n) for n=0..82.

Crossrefs

Cf. A000217, A000290, A014134, A000124, A231354.

Sequence in context: A078879 A082859 A083537 * A135830 A339846 A029353

Adjacent sequences: A231350 A231351 A231352 * A231354 A231355 A231356

Keyword

sign

Author

Alex Ratushnyak, Nov 08 2013

Status

approved