A079257 - cp's OEIS frontend

A079257 a(n) is taken to be the smallest positive integer greater than a(n-1) which is consistent with the condition "n is a member of the sequence if and only if a(n) is a triangular number".

n	a(n)
0	0
1	1
2	4
3	5
4	6
5	10
6	15
7	16
8	17
9	18
10	21
11	22
12	23
13	24
14	25
15	28
16	36
17	45
18	55
19	56
20	57
21	66
22	78
23	91
24	105
25	120
26	121
27	122
28	136
29	137
30	138
31	139
32	140
33	141
34	142
35	143
36	153
37	154
38	155
39	156
40	157
41	158
42	159
43	160
44	161
45	171
46	172
47	173
48	174
49	175
50	176
51	177
52	178
53	179
54	180
55	190
56	210
57	231

[0, 1, 4, 5, 6, 10, 15, 16, 17, 18, 21, 22, 23, 24, 25, 28, 36, 45, 55, 56, 57, 66, 78, 91, 105, 120, 121, 122, 136, 137, 138, 139, 140, 141, 142, 143, 153, 154, 155, 156, 157, 158, 159, 160, 161, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 190, 210, 231]

cp's OEIS Frontend

A079257 a(n) is taken to be the smallest positive integer greater than a(n-1) which is consistent with the condition "n is a member of the sequence if and only if a(n) is a triangular number".

Table of values

List of values

n	a(n)
0	0
1	1
2	4
3	5
4	6
5	10
6	15
7	16
8	17
9	18
10	21
11	22
12	23
13	24
14	25
15	28
16	36
17	45
18	55
19	56
20	57
21	66
22	78
23	91
24	105
25	120
26	121
27	122
28	136
29	137
30	138
31	139
32	140
33	141
34	142
35	143
36	153
37	154
38	155
39	156
40	157
41	158
42	159
43	160
44	161
45	171
46	172
47	173
48	174
49	175
50	176
51	177
52	178
53	179
54	180
55	190
56	210
57	231

n	a(n)
0	0
1	1
2	4
3	5
4	6
5	10
6	15
7	16
8	17
9	18
10	21
11	22
12	23
13	24
14	25
15	28
16	36
17	45
18	55
19	56
20	57
21	66
22	78
23	91
24	105
25	120
26	121
27	122
28	136
29	137
30	138
31	139
32	140
33	141
34	142
35	143
36	153
37	154
38	155
39	156
40	157
41	158
42	159
43	160
44	161
45	171
46	172
47	173
48	174
49	175
50	176
51	177
52	178
53	179
54	180
55	190
56	210
57	231

n	a(n)
0	0
1	1
2	4
3	5
4	6
5	10
6	15
7	16
8	17
9	18
10	21
11	22
12	23
13	24
14	25
15	28
16	36
17	45
18	55
19	56
20	57
21	66
22	78
23	91
24	105
25	120
26	121
27	122
28	136
29	137
30	138
31	139
32	140
33	141
34	142
35	143
36	153
37	154
38	155
39	156
40	157
41	158
42	159
43	160
44	161
45	171
46	172
47	173
48	174
49	175
50	176
51	177
52	178
53	179
54	180
55	190
56	210
57	231