A065225 - cp's OEIS frontend

A065225 Fill a triangular array by rows by writing numbers 1 up to b(0), 1 up to b(1), etc., where b(n) are the 9-gonal (nonagonal) numbers. The final elements of the rows form a(n).

n	a(n)
0	1
1	2
2	5
3	9
4	5
5	11
6	18
7	2
8	11
9	21
10	32
11	44
12	11
13	25
14	40
15	56
16	73
17	16
18	35
19	55
20	76
21	98
22	10
23	34
24	59
25	85
26	112
27	140
28	15
29	45
30	76
31	108
32	141
33	175
34	6
35	42
36	79
37	117
38	156
39	196
40	237
41	18
42	61
43	105
44	150
45	196
46	243
47	291
48	15
49	65
50	116
51	168
52	221
53	275
54	330
55	386
56	47
57	105
58	164
59	224
60	285
61	347
62	410

[1, 2, 5, 9, 5, 11, 18, 2, 11, 21, 32, 44, 11, 25, 40, 56, 73, 16, 35, 55, 76, 98, 10, 34, 59, 85, 112, 140, 15, 45, 76, 108, 141, 175, 6, 42, 79, 117, 156, 196, 237, 18, 61, 105, 150, 196, 243, 291, 15, 65, 116, 168, 221, 275, 330, 386, 47, 105, 164, 224, 285, 347, 410]

cp's OEIS Frontend

A065225 Fill a triangular array by rows by writing numbers 1 up to b(0), 1 up to b(1), etc., where b(n) are the 9-gonal (nonagonal) numbers. The final elements of the rows form a(n).

Table of values

List of values

n	a(n)
0	1
1	2
2	5
3	9
4	5
5	11
6	18
7	2
8	11
9	21
10	32
11	44
12	11
13	25
14	40
15	56
16	73
17	16
18	35
19	55
20	76
21	98
22	10
23	34
24	59
25	85
26	112
27	140
28	15
29	45
30	76
31	108
32	141
33	175
34	6
35	42
36	79
37	117
38	156
39	196
40	237
41	18
42	61
43	105
44	150
45	196
46	243
47	291
48	15
49	65
50	116
51	168
52	221
53	275
54	330
55	386
56	47
57	105
58	164
59	224
60	285
61	347
62	410

n	a(n)
0	1
1	2
2	5
3	9
4	5
5	11
6	18
7	2
8	11
9	21
10	32
11	44
12	11
13	25
14	40
15	56
16	73
17	16
18	35
19	55
20	76
21	98
22	10
23	34
24	59
25	85
26	112
27	140
28	15
29	45
30	76
31	108
32	141
33	175
34	6
35	42
36	79
37	117
38	156
39	196
40	237
41	18
42	61
43	105
44	150
45	196
46	243
47	291
48	15
49	65
50	116
51	168
52	221
53	275
54	330
55	386
56	47
57	105
58	164
59	224
60	285
61	347
62	410

n	a(n)
0	1
1	2
2	5
3	9
4	5
5	11
6	18
7	2
8	11
9	21
10	32
11	44
12	11
13	25
14	40
15	56
16	73
17	16
18	35
19	55
20	76
21	98
22	10
23	34
24	59
25	85
26	112
27	140
28	15
29	45
30	76
31	108
32	141
33	175
34	6
35	42
36	79
37	117
38	156
39	196
40	237
41	18
42	61
43	105
44	150
45	196
46	243
47	291
48	15
49	65
50	116
51	168
52	221
53	275
54	330
55	386
56	47
57	105
58	164
59	224
60	285
61	347
62	410