A097291 Contains exactly once every pair (i,j) of positive integers.

1, 1, 2, 2, 1, 3, 3, 2, 3, 1, 4, 4, 2, 4, 3, 4, 1, 5, 5, 2, 5, 3, 5, 4, 5, 1, 6, 6, 2, 6, 3, 6, 4, 6, 5, 6, 1, 7, 7, 2, 7, 3, 7, 4, 7, 5, 7, 6, 7, 1, 8, 8, 2, 8, 3, 8, 4, 8, 5, 8, 6, 8, 7, 8, 1, 9, 9, 2, 9, 3, 9, 4, 9, 5, 9, 6, 9, 7, 9, 8, 9, 1, 10, 10, 2, 10, 3, 10, 4, 10, 5, 10, 6, 10, 7, 10, 8, 10, 9, 10

Offset

1,3

Comments

The pairs (i,j) are ordered in segments thus: segment 1: 1 segment 2: 1 2 2 segment 3: 1 3 3 2 3 segment 4: 1 4 4 2 4 3 4 segment 5: 1 5 5 2 5 3 5 4 5 and so on.

Links

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

Crossrefs

Cf. A098289.

Sequence in context: A182535 A181186 A364197 * A269501 A254044 A274515

Adjacent sequences: A097288 A097289 A097290 * A097292 A097293 A097294

Keyword

nonn

Author

Clark Kimberling, Aug 05 2004

Status

approved