A181337 - cp's OEIS frontend

A181337 Number of even entries in the top rows of all 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	1
2	6
3	28
4	123
5	512
6	2064
7	8124
8	31416
9	119820
10	451972
11	1689532
12	6268276
13	23107836
14	84721796
15	309151932
16	1123431812
17	4067533244
18	14679173444
19	52821023932
20	189571527236
21	678748381372
22	2424976195396
23	8646702275772

[0, 1, 6, 28, 123, 512, 2064, 8124, 31416, 119820, 451972, 1689532, 6268276, 23107836, 84721796, 309151932, 1123431812, 4067533244, 14679173444, 52821023932, 189571527236, 678748381372, 2424976195396, 8646702275772]

cp's OEIS Frontend

A181337 Number of even entries in the top rows of all 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