A362931 - cp's OEIS frontend

A362931 a(n) = number of pairs (i,j) in [1..n] X [1..n] with integral harmonic mean 2ij/(i+j).

n	a(n)
1	1
2	2
3	3
4	4
5	5
6	10
7	11
8	12
9	13
10	14
11	15
12	20
13	21
14	22
15	27
16	28
17	29
18	34
19	35
20	40
21	41
22	42
23	43
24	48
25	49
26	50
27	51
28	56
29	57
30	66
31	67
32	68
33	69
34	70
35	75
36	80
37	81
38	82
39	83
40	88
41	89
42	98
43	99
44	100
45	109
46	110
47	111
48	116
49	117
50	118
51	119
52	120
53	121
54	126
55	127
56	132
57	133
58	134
59	135
60	148
61	149
62	150
63	155
64	156
65	157
66	166
67	167
68	168
69	169
70	174
71	175
72	184
73	185
74	186
75	191
76	192
77	197
78	202
79	203
80	208

[1, 2, 3, 4, 5, 10, 11, 12, 13, 14, 15, 20, 21, 22, 27, 28, 29, 34, 35, 40, 41, 42, 43, 48, 49, 50, 51, 56, 57, 66, 67, 68, 69, 70, 75, 80, 81, 82, 83, 88, 89, 98, 99, 100, 109, 110, 111, 116, 117, 118, 119, 120, 121, 126, 127, 132, 133, 134, 135, 148, 149, 150, 155, 156, 157, 166, 167, 168, 169, 174, 175, 184, 185, 186, 191, 192, 197, 202, 203, 208]

cp's OEIS Frontend

A362931 a(n) = number of pairs (i,j) in [1..n] X [1..n] with integral harmonic mean 2ij/(i+j).

Table of values

List of values

n	a(n)
1	1
2	2
3	3
4	4
5	5
6	10
7	11
8	12
9	13
10	14
11	15
12	20
13	21
14	22
15	27
16	28
17	29
18	34
19	35
20	40
21	41
22	42
23	43
24	48
25	49
26	50
27	51
28	56
29	57
30	66
31	67
32	68
33	69
34	70
35	75
36	80
37	81
38	82
39	83
40	88
41	89
42	98
43	99
44	100
45	109
46	110
47	111
48	116
49	117
50	118
51	119
52	120
53	121
54	126
55	127
56	132
57	133
58	134
59	135
60	148
61	149
62	150
63	155
64	156
65	157
66	166
67	167
68	168
69	169
70	174
71	175
72	184
73	185
74	186
75	191
76	192
77	197
78	202
79	203
80	208

n	a(n)
1	1
2	2
3	3
4	4
5	5
6	10
7	11
8	12
9	13
10	14
11	15
12	20
13	21
14	22
15	27
16	28
17	29
18	34
19	35
20	40
21	41
22	42
23	43
24	48
25	49
26	50
27	51
28	56
29	57
30	66
31	67
32	68
33	69
34	70
35	75
36	80
37	81
38	82
39	83
40	88
41	89
42	98
43	99
44	100
45	109
46	110
47	111
48	116
49	117
50	118
51	119
52	120
53	121
54	126
55	127
56	132
57	133
58	134
59	135
60	148
61	149
62	150
63	155
64	156
65	157
66	166
67	167
68	168
69	169
70	174
71	175
72	184
73	185
74	186
75	191
76	192
77	197
78	202
79	203
80	208

cp's OEIS Frontend

A362931 a(n) = number of pairs (i,j) in [1..n] X [1..n] with integral harmonic mean 2*i*j/(i+j).

Table of values

List of values

A362931 a(n) = number of pairs (i,j) in [1..n] X [1..n] with integral harmonic mean 2ij/(i+j).

n	a(n)
1	1
2	2
3	3
4	4
5	5
6	10
7	11
8	12
9	13
10	14
11	15
12	20
13	21
14	22
15	27
16	28
17	29
18	34
19	35
20	40
21	41
22	42
23	43
24	48
25	49
26	50
27	51
28	56
29	57
30	66
31	67
32	68
33	69
34	70
35	75
36	80
37	81
38	82
39	83
40	88
41	89
42	98
43	99
44	100
45	109
46	110
47	111
48	116
49	117
50	118
51	119
52	120
53	121
54	126
55	127
56	132
57	133
58	134
59	135
60	148
61	149
62	150
63	155
64	156
65	157
66	166
67	167
68	168
69	169
70	174
71	175
72	184
73	185
74	186
75	191
76	192
77	197
78	202
79	203
80	208