A163990 - cp's OEIS frontend

A163990 Square array read by antidiagonals where the row n lists the numbers k such that their largest divisor <= sqrt(k) equals n.

n	a(n)
1	1
2	4
3	2
4	9
5	6
6	3
7	16
8	12
9	8
10	5
11	25
12	20
13	15
14	10
15	7
16	36
17	30
18	24
19	18
20	14
21	11
22	49
23	42
24	35
25	28
26	21
27	22
28	13
29	64
30	56
31	48
32	40
33	32
34	27
35	26
36	17
37	81
38	72
39	63
40	54
41	45
42	44
43	33
44	34
45	19
46	100
47	90
48	80
49	70
50	60
51	50
52	52
53	39
54	38
55	23
56	121
57	110
58	99
59	88
60	77
61	66
62	55
63	68
64	51
65	46
66	29
67	144
68	132
69	120
70	108

[1, 4, 2, 9, 6, 3, 16, 12, 8, 5, 25, 20, 15, 10, 7, 36, 30, 24, 18, 14, 11, 49, 42, 35, 28, 21, 22, 13, 64, 56, 48, 40, 32, 27, 26, 17, 81, 72, 63, 54, 45, 44, 33, 34, 19, 100, 90, 80, 70, 60, 50, 52, 39, 38, 23, 121, 110, 99, 88, 77, 66, 55, 68, 51, 46, 29, 144, 132, 120, 108]

cp's OEIS Frontend

A163990 Square array read by antidiagonals where the row n lists the numbers k such that their largest divisor <= sqrt(k) equals n.

Table of values

List of values

n	a(n)
1	1
2	4
3	2
4	9
5	6
6	3
7	16
8	12
9	8
10	5
11	25
12	20
13	15
14	10
15	7
16	36
17	30
18	24
19	18
20	14
21	11
22	49
23	42
24	35
25	28
26	21
27	22
28	13
29	64
30	56
31	48
32	40
33	32
34	27
35	26
36	17
37	81
38	72
39	63
40	54
41	45
42	44
43	33
44	34
45	19
46	100
47	90
48	80
49	70
50	60
51	50
52	52
53	39
54	38
55	23
56	121
57	110
58	99
59	88
60	77
61	66
62	55
63	68
64	51
65	46
66	29
67	144
68	132
69	120
70	108

n	a(n)
1	1
2	4
3	2
4	9
5	6
6	3
7	16
8	12
9	8
10	5
11	25
12	20
13	15
14	10
15	7
16	36
17	30
18	24
19	18
20	14
21	11
22	49
23	42
24	35
25	28
26	21
27	22
28	13
29	64
30	56
31	48
32	40
33	32
34	27
35	26
36	17
37	81
38	72
39	63
40	54
41	45
42	44
43	33
44	34
45	19
46	100
47	90
48	80
49	70
50	60
51	50
52	52
53	39
54	38
55	23
56	121
57	110
58	99
59	88
60	77
61	66
62	55
63	68
64	51
65	46
66	29
67	144
68	132
69	120
70	108

n	a(n)
1	1
2	4
3	2
4	9
5	6
6	3
7	16
8	12
9	8
10	5
11	25
12	20
13	15
14	10
15	7
16	36
17	30
18	24
19	18
20	14
21	11
22	49
23	42
24	35
25	28
26	21
27	22
28	13
29	64
30	56
31	48
32	40
33	32
34	27
35	26
36	17
37	81
38	72
39	63
40	54
41	45
42	44
43	33
44	34
45	19
46	100
47	90
48	80
49	70
50	60
51	50
52	52
53	39
54	38
55	23
56	121
57	110
58	99
59	88
60	77
61	66
62	55
63	68
64	51
65	46
66	29
67	144
68	132
69	120
70	108