A181301 - cp's OEIS frontend

A181301 Number of 2-compositions of n having no column with equal entries. A 2-composition of n is a nonnegative matrix with two rows, such that each column has at least one nonzero entry and whose entries sum up to n.

n	a(n)
0	1
1	2
2	6
3	20
4	64
5	206
6	662
7	2128
8	6840
9	21986
10	70670
11	227156
12	730152
13	2346942
14	7543822
15	24248256
16	77941648
17	250529378
18	805281526
19	2588432308
20	8320049072
21	26743297998
22	85961510758
23	276307781200
24	888141556360
25	2854770939522

[1, 2, 6, 20, 64, 206, 662, 2128, 6840, 21986, 70670, 227156, 730152, 2346942, 7543822, 24248256, 77941648, 250529378, 805281526, 2588432308, 8320049072, 26743297998, 85961510758, 276307781200, 888141556360, 2854770939522]

cp's OEIS Frontend

A181301 Number of 2-compositions of n having no column with equal entries. A 2-composition of n is a nonnegative matrix with two rows, such that each column has at least one nonzero entry and whose entries sum up to n.

Table of values

List of values