A259260 - cp's OEIS frontend

A259260 With a(1) = 1, a(n) is the smallest number not already in the sequence such that the arithmetic mean of two neighboring terms is a square.

n	a(n)
1	1
2	7
3	11
4	21
5	29
6	3
7	5
8	13
9	19
10	31
11	41
12	9
13	23
14	27
15	45
16	53
17	75
18	87
19	113
20	15
21	17
22	33
23	39
24	59
25	69
26	93
27	35
28	37
29	61
30	67
31	95
32	105
33	57
34	71
35	91
36	109
37	133
38	155
39	183
40	209
41	79
42	49
43	151
44	137
45	25
46	47
47	51
48	77
49	85
50	43
51	55
52	73
53	89
54	111
55	131
56	157
57	181
58	107
59	135
60	65
61	63
62	99
63	101
64	141
65	147
66	191
67	97
68	103
69	139
70	149
71	189
72	203
73	247
74	145

[1, 7, 11, 21, 29, 3, 5, 13, 19, 31, 41, 9, 23, 27, 45, 53, 75, 87, 113, 15, 17, 33, 39, 59, 69, 93, 35, 37, 61, 67, 95, 105, 57, 71, 91, 109, 133, 155, 183, 209, 79, 49, 151, 137, 25, 47, 51, 77, 85, 43, 55, 73, 89, 111, 131, 157, 181, 107, 135, 65, 63, 99, 101, 141, 147, 191, 97, 103, 139, 149, 189, 203, 247, 145]

cp's OEIS Frontend

A259260 With a(1) = 1, a(n) is the smallest number not already in the sequence such that the arithmetic mean of two neighboring terms is a square.

Table of values

List of values

n	a(n)
1	1
2	7
3	11
4	21
5	29
6	3
7	5
8	13
9	19
10	31
11	41
12	9
13	23
14	27
15	45
16	53
17	75
18	87
19	113
20	15
21	17
22	33
23	39
24	59
25	69
26	93
27	35
28	37
29	61
30	67
31	95
32	105
33	57
34	71
35	91
36	109
37	133
38	155
39	183
40	209
41	79
42	49
43	151
44	137
45	25
46	47
47	51
48	77
49	85
50	43
51	55
52	73
53	89
54	111
55	131
56	157
57	181
58	107
59	135
60	65
61	63
62	99
63	101
64	141
65	147
66	191
67	97
68	103
69	139
70	149
71	189
72	203
73	247
74	145

n	a(n)
1	1
2	7
3	11
4	21
5	29
6	3
7	5
8	13
9	19
10	31
11	41
12	9
13	23
14	27
15	45
16	53
17	75
18	87
19	113
20	15
21	17
22	33
23	39
24	59
25	69
26	93
27	35
28	37
29	61
30	67
31	95
32	105
33	57
34	71
35	91
36	109
37	133
38	155
39	183
40	209
41	79
42	49
43	151
44	137
45	25
46	47
47	51
48	77
49	85
50	43
51	55
52	73
53	89
54	111
55	131
56	157
57	181
58	107
59	135
60	65
61	63
62	99
63	101
64	141
65	147
66	191
67	97
68	103
69	139
70	149
71	189
72	203
73	247
74	145

n	a(n)
1	1
2	7
3	11
4	21
5	29
6	3
7	5
8	13
9	19
10	31
11	41
12	9
13	23
14	27
15	45
16	53
17	75
18	87
19	113
20	15
21	17
22	33
23	39
24	59
25	69
26	93
27	35
28	37
29	61
30	67
31	95
32	105
33	57
34	71
35	91
36	109
37	133
38	155
39	183
40	209
41	79
42	49
43	151
44	137
45	25
46	47
47	51
48	77
49	85
50	43
51	55
52	73
53	89
54	111
55	131
56	157
57	181
58	107
59	135
60	65
61	63
62	99
63	101
64	141
65	147
66	191
67	97
68	103
69	139
70	149
71	189
72	203
73	247
74	145