A225986 - cp's OEIS frontend

A225986 Number of pairs of orthogonal (-x,y) vectors of length 1*(x+y), where x/y is the n-th rational <= 1, ordered first by y and then x, e.g. 1/1, 1/2, 1/3, 2/3, 1/4, 3/4 ...

n	a(n)
1	4
2	9
3	20
4	60
5	45
6	420
7	102
8	378
9	1120
10	3024
11	231
12	22176
13	520
14	2376
15	8160
16	23760
17	63360
18	164736
19	1161
20	21780
21	185328
22	1235520
23	2570
24	14190
25	188760
26	544544
27	3660800
28	9335040
29	5643
30	147576
31	11202048
32	70946304
33	12300
34	80028
35	374192
36	1408680

[4, 9, 20, 60, 45, 420, 102, 378, 1120, 3024, 231, 22176, 520, 2376, 8160, 23760, 63360, 164736, 1161, 21780, 185328, 1235520, 2570, 14190, 188760, 544544, 3660800, 9335040, 5643, 147576, 11202048, 70946304, 12300, 80028, 374192, 1408680]

cp's OEIS Frontend

A225986 Number of pairs of orthogonal (-x,y) vectors of length 1*(x+y), where x/y is the n-th rational <= 1, ordered first by y and then x, e.g. 1/1, 1/2, 1/3, 2/3, 1/4, 3/4 ...

Table of values

List of values