A128905 - cp's OEIS frontend

A128905 Numbers k such that the k-th triangular number has exactly four distinct prime factors.

n	a(n)
1	20
2	51
3	59
4	60
5	65
6	68
7	69
8	76
9	77
10	83
11	91
12	92
13	105
14	110
15	114
16	115
17	123
18	129
19	131
20	139
21	154
22	156
23	165
24	182
25	185
26	186
27	187
28	194
29	210
30	212
31	221
32	227
33	228
34	235
35	236
36	237
37	246
38	254
39	258
40	265
41	266
42	267
43	273
44	276
45	286
46	290
47	291
48	307
49	309
50	318
51	321
52	322
53	330
54	345

[20, 51, 59, 60, 65, 68, 69, 76, 77, 83, 91, 92, 105, 110, 114, 115, 123, 129, 131, 139, 154, 156, 165, 182, 185, 186, 187, 194, 210, 212, 221, 227, 228, 235, 236, 237, 246, 254, 258, 265, 266, 267, 273, 276, 286, 290, 291, 307, 309, 318, 321, 322, 330, 345]

cp's OEIS Frontend

A128905 Numbers k such that the k-th triangular number has exactly four distinct prime factors.

Table of values

List of values

n	a(n)
1	20
2	51
3	59
4	60
5	65
6	68
7	69
8	76
9	77
10	83
11	91
12	92
13	105
14	110
15	114
16	115
17	123
18	129
19	131
20	139
21	154
22	156
23	165
24	182
25	185
26	186
27	187
28	194
29	210
30	212
31	221
32	227
33	228
34	235
35	236
36	237
37	246
38	254
39	258
40	265
41	266
42	267
43	273
44	276
45	286
46	290
47	291
48	307
49	309
50	318
51	321
52	322
53	330
54	345

n	a(n)
1	20
2	51
3	59
4	60
5	65
6	68
7	69
8	76
9	77
10	83
11	91
12	92
13	105
14	110
15	114
16	115
17	123
18	129
19	131
20	139
21	154
22	156
23	165
24	182
25	185
26	186
27	187
28	194
29	210
30	212
31	221
32	227
33	228
34	235
35	236
36	237
37	246
38	254
39	258
40	265
41	266
42	267
43	273
44	276
45	286
46	290
47	291
48	307
49	309
50	318
51	321
52	322
53	330
54	345

n	a(n)
1	20
2	51
3	59
4	60
5	65
6	68
7	69
8	76
9	77
10	83
11	91
12	92
13	105
14	110
15	114
16	115
17	123
18	129
19	131
20	139
21	154
22	156
23	165
24	182
25	185
26	186
27	187
28	194
29	210
30	212
31	221
32	227
33	228
34	235
35	236
36	237
37	246
38	254
39	258
40	265
41	266
42	267
43	273
44	276
45	286
46	290
47	291
48	307
49	309
50	318
51	321
52	322
53	330
54	345