A261491 - cp's OEIS frontend

A261491 a(n) = ceiling(2 + sqrt(8*n-4)).

n	a(n)
1	4
2	6
3	7
4	8
5	8
6	9
7	10
8	10
9	11
10	11
11	12
12	12
13	12
14	13
15	13
16	14
17	14
18	14
19	15
20	15
21	15
22	16
23	16
24	16
25	16
26	17
27	17
28	17
29	18
30	18
31	18
32	18
33	19
34	19
35	19
36	19
37	20
38	20
39	20
40	20
41	20
42	21
43	21
44	21
45	21
46	22
47	22
48	22
49	22
50	22
51	23
52	23
53	23
54	23
55	23
56	24
57	24
58	24
59	24
60	24
61	24
62	25
63	25
64	25
65	25
66	25
67	26
68	26
69	26
70	26
71	26
72	26
73	27
74	27
75	27
76	27
77	27
78	27
79	28
80	28
81	28
82	28
83	28
84	28
85	28
86	29

[4, 6, 7, 8, 8, 9, 10, 10, 11, 11, 12, 12, 12, 13, 13, 14, 14, 14, 15, 15, 15, 16, 16, 16, 16, 17, 17, 17, 18, 18, 18, 18, 19, 19, 19, 19, 20, 20, 20, 20, 20, 21, 21, 21, 21, 22, 22, 22, 22, 22, 23, 23, 23, 23, 23, 24, 24, 24, 24, 24, 24, 25, 25, 25, 25, 25, 26, 26, 26, 26, 26, 26, 27, 27, 27, 27, 27, 27, 28, 28, 28, 28, 28, 28, 28, 29]

cp's OEIS Frontend

A261491 a(n) = ceiling(2 + sqrt(8*n-4)).

Table of values

List of values

n	a(n)
1	4
2	6
3	7
4	8
5	8
6	9
7	10
8	10
9	11
10	11
11	12
12	12
13	12
14	13
15	13
16	14
17	14
18	14
19	15
20	15
21	15
22	16
23	16
24	16
25	16
26	17
27	17
28	17
29	18
30	18
31	18
32	18
33	19
34	19
35	19
36	19
37	20
38	20
39	20
40	20
41	20
42	21
43	21
44	21
45	21
46	22
47	22
48	22
49	22
50	22
51	23
52	23
53	23
54	23
55	23
56	24
57	24
58	24
59	24
60	24
61	24
62	25
63	25
64	25
65	25
66	25
67	26
68	26
69	26
70	26
71	26
72	26
73	27
74	27
75	27
76	27
77	27
78	27
79	28
80	28
81	28
82	28
83	28
84	28
85	28
86	29

n	a(n)
1	4
2	6
3	7
4	8
5	8
6	9
7	10
8	10
9	11
10	11
11	12
12	12
13	12
14	13
15	13
16	14
17	14
18	14
19	15
20	15
21	15
22	16
23	16
24	16
25	16
26	17
27	17
28	17
29	18
30	18
31	18
32	18
33	19
34	19
35	19
36	19
37	20
38	20
39	20
40	20
41	20
42	21
43	21
44	21
45	21
46	22
47	22
48	22
49	22
50	22
51	23
52	23
53	23
54	23
55	23
56	24
57	24
58	24
59	24
60	24
61	24
62	25
63	25
64	25
65	25
66	25
67	26
68	26
69	26
70	26
71	26
72	26
73	27
74	27
75	27
76	27
77	27
78	27
79	28
80	28
81	28
82	28
83	28
84	28
85	28
86	29

n	a(n)
1	4
2	6
3	7
4	8
5	8
6	9
7	10
8	10
9	11
10	11
11	12
12	12
13	12
14	13
15	13
16	14
17	14
18	14
19	15
20	15
21	15
22	16
23	16
24	16
25	16
26	17
27	17
28	17
29	18
30	18
31	18
32	18
33	19
34	19
35	19
36	19
37	20
38	20
39	20
40	20
41	20
42	21
43	21
44	21
45	21
46	22
47	22
48	22
49	22
50	22
51	23
52	23
53	23
54	23
55	23
56	24
57	24
58	24
59	24
60	24
61	24
62	25
63	25
64	25
65	25
66	25
67	26
68	26
69	26
70	26
71	26
72	26
73	27
74	27
75	27
76	27
77	27
78	27
79	28
80	28
81	28
82	28
83	28
84	28
85	28
86	29