A345132 - cp's OEIS frontend

A345132 Number of (n+2) X (n+2) symmetric matrices with nonnegative integer entries, trace 0, with n rows that sum to 2, and 2 rows that sum to 1.

n	a(n)
0	1
1	1
2	3
3	10
4	46
5	252
6	1642
7	12316
8	104730
9	995122
10	10450414
11	120192924
12	1502537932
13	20285580880
14	294156077364
15	4559608340968
16	75236088623548
17	1316668510772124
18	24358939966126900
19	475008770990906488
20	9737844963832507656
21	209366721066736679536

[1, 1, 3, 10, 46, 252, 1642, 12316, 104730, 995122, 10450414, 120192924, 1502537932, 20285580880, 294156077364, 4559608340968, 75236088623548, 1316668510772124, 24358939966126900, 475008770990906488, 9737844963832507656, 209366721066736679536]

cp's OEIS Frontend

A345132 Number of (n+2) X (n+2) symmetric matrices with nonnegative integer entries, trace 0, with n rows that sum to 2, and 2 rows that sum to 1.

Table of values

List of values