A181300 - cp's OEIS frontend

A181300 Number of columns with top entry equal to bottom entry in all the 2-compositions of n. 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	0
1	0
2	1
3	4
4	19
5	80
6	328
7	1304
8	5084
9	19512
10	73976
11	277688
12	1033848
13	3822584
14	14050824
15	51385720
16	187095240
17	678570360
18	2452626312
19	8837584248
20	31756892552
21	113831195000
22	407102551688
23	1452956457336
24	5175872174728

[0, 0, 1, 4, 19, 80, 328, 1304, 5084, 19512, 73976, 277688, 1033848, 3822584, 14050824, 51385720, 187095240, 678570360, 2452626312, 8837584248, 31756892552, 113831195000, 407102551688, 1452956457336, 5175872174728]

cp's OEIS Frontend

A181300 Number of columns with top entry equal to bottom entry in all the 2-compositions of n. 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