A205403 a(n) is the index j < k such that n divides s(k)-s(j) for some j, where s(j) = floor((j+1)^2/2)/2, and k is the least index for which such a j exists.

1, 2, 1, 2, 1, 4, 2, 1, 2, 2, 1, 3, 6, 2, 1, 3, 2, 2, 1, 7, 3, 8, 2, 1, 4, 3, 5, 2, 1, 4, 9, 3, 5, 2, 1, 4, 6, 3, 9, 2, 1, 10, 4, 6, 3, 15, 2, 1, 2, 4, 10, 3, 3, 2, 1, 7, 15, 4, 20, 3, 8, 2, 1, 11, 7, 4, 5, 3, 6, 2, 1, 5, 11, 7, 4, 14, 3, 6, 2, 1

Offset

1,2

Comments

For a guide to related sequences, see A204892.

Links

Table of n, a(n) for n=1..80.

Mathematica

(See the program at A205402.)

Crossrefs

Cf. A205402, A204892.

Sequence in context: A321368 A338508 A100380 * A080825 A229724 A034693

Adjacent sequences: A205400 A205401 A205402 * A205404 A205405 A205406

Keyword

nonn

Author

Clark Kimberling, Jan 27 2012

Extensions

Definition corrected by Clark Kimberling, Dec 05 2021

Status

approved