A284551 - cp's OEIS frontend

A284551 Triangular array read by rows, demonstrating that the difference between a pentagonal number (left edge of triangle) and a square (right edge) is a triangular number.

n	a(n)
1	1
2	5
3	4
4	12
5	11
6	9
7	22
8	21
9	19
10	16
11	35
12	34
13	32
14	29
15	25
16	51
17	50
18	48
19	45
20	41
21	36
22	70
23	69
24	67
25	64
26	60
27	55
28	49
29	92
30	91
31	89
32	86
33	82
34	77
35	71
36	64
37	117
38	116
39	114
40	111
41	107
42	102
43	96
44	89
45	81
46	145
47	144
48	142
49	139
50	135
51	130
52	124
53	117
54	109
55	100
56	176
57	175
58	173
59	170
60	166
61	161
62	155
63	148
64	140
65	131
66	121
67	210
68	209

[1, 5, 4, 12, 11, 9, 22, 21, 19, 16, 35, 34, 32, 29, 25, 51, 50, 48, 45, 41, 36, 70, 69, 67, 64, 60, 55, 49, 92, 91, 89, 86, 82, 77, 71, 64, 117, 116, 114, 111, 107, 102, 96, 89, 81, 145, 144, 142, 139, 135, 130, 124, 117, 109, 100, 176, 175, 173, 170, 166, 161, 155, 148, 140, 131, 121, 210, 209]

cp's OEIS Frontend

A284551 Triangular array read by rows, demonstrating that the difference between a pentagonal number (left edge of triangle) and a square (right edge) is a triangular number.

Table of values

List of values

n	a(n)
1	1
2	5
3	4
4	12
5	11
6	9
7	22
8	21
9	19
10	16
11	35
12	34
13	32
14	29
15	25
16	51
17	50
18	48
19	45
20	41
21	36
22	70
23	69
24	67
25	64
26	60
27	55
28	49
29	92
30	91
31	89
32	86
33	82
34	77
35	71
36	64
37	117
38	116
39	114
40	111
41	107
42	102
43	96
44	89
45	81
46	145
47	144
48	142
49	139
50	135
51	130
52	124
53	117
54	109
55	100
56	176
57	175
58	173
59	170
60	166
61	161
62	155
63	148
64	140
65	131
66	121
67	210
68	209

n	a(n)
1	1
2	5
3	4
4	12
5	11
6	9
7	22
8	21
9	19
10	16
11	35
12	34
13	32
14	29
15	25
16	51
17	50
18	48
19	45
20	41
21	36
22	70
23	69
24	67
25	64
26	60
27	55
28	49
29	92
30	91
31	89
32	86
33	82
34	77
35	71
36	64
37	117
38	116
39	114
40	111
41	107
42	102
43	96
44	89
45	81
46	145
47	144
48	142
49	139
50	135
51	130
52	124
53	117
54	109
55	100
56	176
57	175
58	173
59	170
60	166
61	161
62	155
63	148
64	140
65	131
66	121
67	210
68	209

n	a(n)
1	1
2	5
3	4
4	12
5	11
6	9
7	22
8	21
9	19
10	16
11	35
12	34
13	32
14	29
15	25
16	51
17	50
18	48
19	45
20	41
21	36
22	70
23	69
24	67
25	64
26	60
27	55
28	49
29	92
30	91
31	89
32	86
33	82
34	77
35	71
36	64
37	117
38	116
39	114
40	111
41	107
42	102
43	96
44	89
45	81
46	145
47	144
48	142
49	139
50	135
51	130
52	124
53	117
54	109
55	100
56	176
57	175
58	173
59	170
60	166
61	161
62	155
63	148
64	140
65	131
66	121
67	210
68	209