A258490 - cp's OEIS frontend

A258490 Number of words of length 2n such that all letters of the ternary alphabet occur at least once and are introduced in ascending order and which can be built by repeatedly inserting doublets into the initially empty word.

n	a(n)
3	5
4	56
5	465
6	3509
7	25571
8	184232
9	1325609
10	9567545
11	69387483
12	505915981
13	3708195075
14	27314663271
15	202116910415
16	1501769001416
17	11200258810265
18	83815491037841
19	629152465444715
20	4735907436066401
21	35740538971518155
22	270356740041089471
23	2049510329494271615

[5, 56, 465, 3509, 25571, 184232, 1325609, 9567545, 69387483, 505915981, 3708195075, 27314663271, 202116910415, 1501769001416, 11200258810265, 83815491037841, 629152465444715, 4735907436066401, 35740538971518155, 270356740041089471, 2049510329494271615]

cp's OEIS Frontend

A258490 Number of words of length 2n such that all letters of the ternary alphabet occur at least once and are introduced in ascending order and which can be built by repeatedly inserting doublets into the initially empty word.

Table of values

List of values