A381228 Smallest k such that n appears in row k of the triangle in A381227, or -1 if n never appears in A381227.

1, 2, 3, 4, 4, 3, 10, 7, 7, 5, 5, 12, 12, 8, 8, 13, 13, 21, 36, 22, 22, 37, 14, 4, 9, 6, 6, 39, 39, 24, 24, 15, 15, 69, 41, 41, 25, 25, 42, 42, 72, 72, 10, 10, 43, 16, 16, 74, 128, 44, 44, 75, 130, 76, 76, 27, 27, 77, 77, 134, 134, 78, 46, 46, 17, 17, 79, 79, 28

Offset

1,2

Comments

Conjecture: Every positive integer appears in A381227.

Links

Table of n, a(n) for n=1..69.

Example

14 first appears in row 8 of A381227, so a(14) = 8.

Crossrefs

Cf. A139004, A381226, A381227, A381229.

Sequence in context: A364392 A366681 A241283 * A274095 A263408 A109870

Adjacent sequences: A381225 A381226 A381227 * A381229 A381230 A381231

Keyword

nonn,changed

Author

N. J. A. Sloane, Feb 25 2025

Extensions

More terms from Jinyuan Wang, Feb 25 2025

Status

approved