A218474 - cp's OEIS frontend

A218474 Number of 3n-length 4-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	10
3	127
4	1810
5	27631
6	441604
7	7293700
8	123485914
9	2131511455
10	37368531010
11	663539143015
12	11908626395320
13	215670579863428
14	3936425910379840
15	72335601620713432
16	1337149262553687658
17	24847762997547701695
18	463900901255209923310
19	8697278488612398979645

[1, 1, 10, 127, 1810, 27631, 441604, 7293700, 123485914, 2131511455, 37368531010, 663539143015, 11908626395320, 215670579863428, 3936425910379840, 72335601620713432, 1337149262553687658, 24847762997547701695, 463900901255209923310, 8697278488612398979645]

cp's OEIS Frontend

A218474 Number of 3n-length 4-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