A008497 - cp's OEIS frontend

A008497 a(n) = floor(n/5)*floor((n+1)/5).

n	a(n)
0	0
1	0
2	0
3	0
4	0
5	1
6	1
7	1
8	1
9	2
10	4
11	4
12	4
13	4
14	6
15	9
16	9
17	9
18	9
19	12
20	16
21	16
22	16
23	16
24	20
25	25
26	25
27	25
28	25
29	30
30	36
31	36
32	36
33	36
34	42
35	49
36	49
37	49
38	49
39	56
40	64
41	64
42	64
43	64
44	72
45	81
46	81
47	81
48	81
49	90
50	100
51	100
52	100
53	100
54	110
55	121
56	121
57	121
58	121

[0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 4, 4, 4, 4, 6, 9, 9, 9, 9, 12, 16, 16, 16, 16, 20, 25, 25, 25, 25, 30, 36, 36, 36, 36, 42, 49, 49, 49, 49, 56, 64, 64, 64, 64, 72, 81, 81, 81, 81, 90, 100, 100, 100, 100, 110, 121, 121, 121, 121]

cp's OEIS Frontend

A008497 a(n) = floor(n/5)*floor((n+1)/5).

Table of values

List of values

n	a(n)
0	0
1	0
2	0
3	0
4	0
5	1
6	1
7	1
8	1
9	2
10	4
11	4
12	4
13	4
14	6
15	9
16	9
17	9
18	9
19	12
20	16
21	16
22	16
23	16
24	20
25	25
26	25
27	25
28	25
29	30
30	36
31	36
32	36
33	36
34	42
35	49
36	49
37	49
38	49
39	56
40	64
41	64
42	64
43	64
44	72
45	81
46	81
47	81
48	81
49	90
50	100
51	100
52	100
53	100
54	110
55	121
56	121
57	121
58	121

n	a(n)
0	0
1	0
2	0
3	0
4	0
5	1
6	1
7	1
8	1
9	2
10	4
11	4
12	4
13	4
14	6
15	9
16	9
17	9
18	9
19	12
20	16
21	16
22	16
23	16
24	20
25	25
26	25
27	25
28	25
29	30
30	36
31	36
32	36
33	36
34	42
35	49
36	49
37	49
38	49
39	56
40	64
41	64
42	64
43	64
44	72
45	81
46	81
47	81
48	81
49	90
50	100
51	100
52	100
53	100
54	110
55	121
56	121
57	121
58	121

n	a(n)
0	0
1	0
2	0
3	0
4	0
5	1
6	1
7	1
8	1
9	2
10	4
11	4
12	4
13	4
14	6
15	9
16	9
17	9
18	9
19	12
20	16
21	16
22	16
23	16
24	20
25	25
26	25
27	25
28	25
29	30
30	36
31	36
32	36
33	36
34	42
35	49
36	49
37	49
38	49
39	56
40	64
41	64
42	64
43	64
44	72
45	81
46	81
47	81
48	81
49	90
50	100
51	100
52	100
53	100
54	110
55	121
56	121
57	121
58	121