A218473 - cp's OEIS frontend

A218473 Number of 3n-length 3-ary words, either empty or beginning with the first letter of the alphabet, that can be built by repeatedly inserting triples of identical letters into the initially empty word.

n	a(n)
0	1
1	1
2	7
3	61
4	591
5	6101
6	65719
7	729933
8	8297247
9	96044101
10	1128138567
11	13411861629
12	161066465583
13	1950996039669
14	23808159962839
15	292413627476141
16	3611870017079871
17	44838216520062117
18	559127724970143079
19	7000374603097246173
20	87964883375131331151

[1, 1, 7, 61, 591, 6101, 65719, 729933, 8297247, 96044101, 1128138567, 13411861629, 161066465583, 1950996039669, 23808159962839, 292413627476141, 3611870017079871, 44838216520062117, 559127724970143079, 7000374603097246173, 87964883375131331151]

cp's OEIS Frontend

A218473 Number of 3n-length 3-ary words, either empty or beginning with the first letter of the alphabet, that can be built by repeatedly inserting triples of identical letters into the initially empty word.

Table of values

List of values