A333889 - cp's OEIS frontend

A333889 Number of non-isomorphic n X n nonnegative integer symmetric matrices with all row and column sums equal to 4 up to permutations of rows and columns.

n	a(n)
0	1
1	1
2	3
3	9
4	33
5	142
6	742
7	4454
8	30516
9	233574
10	1972430
11	18190806
12	181774873
13	1955268162
14	22516241557
15	276294103003
16	3598106433662
17	49551992313623
18	719398127720459
19	10979514511427858
20	175716291405379723
21	2942195925987952412
22	51436169813668249174
23	937106275320950472387
24	17761791825490936694507

[1, 1, 3, 9, 33, 142, 742, 4454, 30516, 233574, 1972430, 18190806, 181774873, 1955268162, 22516241557, 276294103003, 3598106433662, 49551992313623, 719398127720459, 10979514511427858, 175716291405379723, 2942195925987952412, 51436169813668249174, 937106275320950472387, 17761791825490936694507]

cp's OEIS Frontend

A333889 Number of non-isomorphic n X n nonnegative integer symmetric matrices with all row and column sums equal to 4 up to permutations of rows and columns.

Table of values

List of values