A287864 - cp's OEIS frontend

A287864 Consider a symmetric pyramid-shaped chessboard with rows of squares of lengths n, n-2, n-4, ..., ending with either 2 or 1 squares; a(n) is the maximal number of mutually non-attacking queens that can be placed on this board.

n	a(n)
1	1
2	1
3	1
4	2
5	2
6	3
7	3
8	4
9	4
10	5
11	5
12	6
13	6
14	6
15	7
16	7
17	8
18	8
19	9
20	9
21	10
22	10
23	11
24	11
25	12
26	12
27	13
28	13
29	13
30	14
31	14
32	15
33	15
34	16
35	16
36	17
37	17
38	18
39	18
40	19
41	19
42	20
43	20
44	21
45	21
46	21
47	22
48	22
49	23
50	23

[1, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 6, 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13, 13, 14, 14, 15, 15, 16, 16, 17, 17, 18, 18, 19, 19, 20, 20, 21, 21, 21, 22, 22, 23, 23]

cp's OEIS Frontend

A287864 Consider a symmetric pyramid-shaped chessboard with rows of squares of lengths n, n-2, n-4, ..., ending with either 2 or 1 squares; a(n) is the maximal number of mutually non-attacking queens that can be placed on this board.

Table of values

List of values

n	a(n)
1	1
2	1
3	1
4	2
5	2
6	3
7	3
8	4
9	4
10	5
11	5
12	6
13	6
14	6
15	7
16	7
17	8
18	8
19	9
20	9
21	10
22	10
23	11
24	11
25	12
26	12
27	13
28	13
29	13
30	14
31	14
32	15
33	15
34	16
35	16
36	17
37	17
38	18
39	18
40	19
41	19
42	20
43	20
44	21
45	21
46	21
47	22
48	22
49	23
50	23

n	a(n)
1	1
2	1
3	1
4	2
5	2
6	3
7	3
8	4
9	4
10	5
11	5
12	6
13	6
14	6
15	7
16	7
17	8
18	8
19	9
20	9
21	10
22	10
23	11
24	11
25	12
26	12
27	13
28	13
29	13
30	14
31	14
32	15
33	15
34	16
35	16
36	17
37	17
38	18
39	18
40	19
41	19
42	20
43	20
44	21
45	21
46	21
47	22
48	22
49	23
50	23

n	a(n)
1	1
2	1
3	1
4	2
5	2
6	3
7	3
8	4
9	4
10	5
11	5
12	6
13	6
14	6
15	7
16	7
17	8
18	8
19	9
20	9
21	10
22	10
23	11
24	11
25	12
26	12
27	13
28	13
29	13
30	14
31	14
32	15
33	15
34	16
35	16
36	17
37	17
38	18
39	18
40	19
41	19
42	20
43	20
44	21
45	21
46	21
47	22
48	22
49	23
50	23