A189886 - cp's OEIS frontend

A189886 a(n) is the number of compositions of the set {1, 2, ..., n} into blocks, each of size 1, 2 or 3 (n >= 0).

n	a(n)
0	1
1	1
2	3
3	13
4	74
5	530
6	4550
7	45570
8	521640
9	6717480
10	96117000
11	1512819000
12	25975395600
13	483169486800
14	9678799930800
15	207733600074000
16	4755768505488000
17	115681418156304000
18	2979408725813520000
19	80998627977002736000
20	2317937034142810080000
21	69649003197501567840000
22	2192459412316607834400000
23	72152830779716793506400000
24	2477756318984329979756160000

[1, 1, 3, 13, 74, 530, 4550, 45570, 521640, 6717480, 96117000, 1512819000, 25975395600, 483169486800, 9678799930800, 207733600074000, 4755768505488000, 115681418156304000, 2979408725813520000, 80998627977002736000, 2317937034142810080000, 69649003197501567840000, 2192459412316607834400000, 72152830779716793506400000, 2477756318984329979756160000]

cp's OEIS Frontend

A189886 a(n) is the number of compositions of the set {1, 2, ..., n} into blocks, each of size 1, 2 or 3 (n >= 0).

Table of values

List of values