A258491 - cp's OEIS frontend

A258491 Number of words of length 2n such that all letters of the quaternary 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)
4	14
5	300
6	4400
7	55692
8	657370
9	7488228
10	83752760
11	928406556
12	10254052556
13	113186465340
14	1250820198264
15	13852280754980
16	153813849202674
17	1712835575525140
18	19129590267619304
19	214261857777632700
20	2406509409480345364
21	27100348605141932540
22	305944173898725745944

[14, 300, 4400, 55692, 657370, 7488228, 83752760, 928406556, 10254052556, 113186465340, 1250820198264, 13852280754980, 153813849202674, 1712835575525140, 19129590267619304, 214261857777632700, 2406509409480345364, 27100348605141932540, 305944173898725745944]

cp's OEIS Frontend

A258491 Number of words of length 2n such that all letters of the quaternary 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