A057027 - cp's OEIS frontend

A057027 Triangle T read by rows: row n consists of the numbers C(n,2)+1 to C(n+1,2); numbers in odd-numbered places form an increasing sequence and the others a decreasing sequence.

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

[1, 2, 3, 4, 6, 5, 7, 10, 8, 9, 11, 15, 12, 14, 13, 16, 21, 17, 20, 18, 19, 22, 28, 23, 27, 24, 26, 25, 29, 36, 30, 35, 31, 34, 32, 33, 37, 45, 38, 44, 39, 43, 40, 42, 41, 46, 55, 47, 54, 48, 53, 49, 52, 50, 51, 56, 66, 57, 65, 58, 64, 59, 63, 60, 62, 61, 67, 78, 68, 77, 69, 76]

cp's OEIS Frontend

A057027 Triangle T read by rows: row n consists of the numbers C(n,2)+1 to C(n+1,2); numbers in odd-numbered places form an increasing sequence and the others a decreasing sequence.

Table of values

List of values

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

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

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