A370499 - cp's OEIS frontend

A370499 a(1) = 1; for n > 1, a(n) is smallest unused number such that a(n) is coprime to a(n-1), sopfr(a(n)) is coprime to sopfr(a(n-1)), Omega(a(n)) does not equal Omega(a(n-1)), the string length of a(n) does not equal the string length of a(n-1), and a(n) has no digit in common with a(n-1), where sopfr(k) is the sum of the primes dividing k, with repetition.

n	a(n)
1	1
2	20
3	7
4	15
5	208
6	5
7	12
8	305
9	17
10	4
11	11
12	6
13	13
14	8
15	19
16	200
17	3
18	10
19	223
20	9
21	23
22	100
23	27
24	101
25	22
26	103
27	24
28	107
29	25
30	104
31	29
32	105
33	2
34	45
35	109
36	26
37	113
38	28
39	111
40	40
41	117
42	32
43	147
44	38
45	127
46	30
47	149
48	33
49	112
50	37
51	102
52	43
53	106
54	47
55	108
56	35
57	124
58	39
59	116
60	49
61	125
62	34
63	151
64	36
65	157
66	42
67	131
68	44
69	115

[1, 20, 7, 15, 208, 5, 12, 305, 17, 4, 11, 6, 13, 8, 19, 200, 3, 10, 223, 9, 23, 100, 27, 101, 22, 103, 24, 107, 25, 104, 29, 105, 2, 45, 109, 26, 113, 28, 111, 40, 117, 32, 147, 38, 127, 30, 149, 33, 112, 37, 102, 43, 106, 47, 108, 35, 124, 39, 116, 49, 125, 34, 151, 36, 157, 42, 131, 44, 115]

cp's OEIS Frontend

Table of values

List of values

n	a(n)
1	1
2	20
3	7
4	15
5	208
6	5
7	12
8	305
9	17
10	4
11	11
12	6
13	13
14	8
15	19
16	200
17	3
18	10
19	223
20	9
21	23
22	100
23	27
24	101
25	22
26	103
27	24
28	107
29	25
30	104
31	29
32	105
33	2
34	45
35	109
36	26
37	113
38	28
39	111
40	40
41	117
42	32
43	147
44	38
45	127
46	30
47	149
48	33
49	112
50	37
51	102
52	43
53	106
54	47
55	108
56	35
57	124
58	39
59	116
60	49
61	125
62	34
63	151
64	36
65	157
66	42
67	131
68	44
69	115

n	a(n)
1	1
2	20
3	7
4	15
5	208
6	5
7	12
8	305
9	17
10	4
11	11
12	6
13	13
14	8
15	19
16	200
17	3
18	10
19	223
20	9
21	23
22	100
23	27
24	101
25	22
26	103
27	24
28	107
29	25
30	104
31	29
32	105
33	2
34	45
35	109
36	26
37	113
38	28
39	111
40	40
41	117
42	32
43	147
44	38
45	127
46	30
47	149
48	33
49	112
50	37
51	102
52	43
53	106
54	47
55	108
56	35
57	124
58	39
59	116
60	49
61	125
62	34
63	151
64	36
65	157
66	42
67	131
68	44
69	115

n	a(n)
1	1
2	20
3	7
4	15
5	208
6	5
7	12
8	305
9	17
10	4
11	11
12	6
13	13
14	8
15	19
16	200
17	3
18	10
19	223
20	9
21	23
22	100
23	27
24	101
25	22
26	103
27	24
28	107
29	25
30	104
31	29
32	105
33	2
34	45
35	109
36	26
37	113
38	28
39	111
40	40
41	117
42	32
43	147
44	38
45	127
46	30
47	149
48	33
49	112
50	37
51	102
52	43
53	106
54	47
55	108
56	35
57	124
58	39
59	116
60	49
61	125
62	34
63	151
64	36
65	157
66	42
67	131
68	44
69	115