A081145 - cp's OEIS frontend

A081145 a(1)=1; thereafter, a(n) is the least positive integer which has not already occurred and is such that |a(n)-a(n-1)| is different from any |a(k)-a(k-1)| which has already occurred.

n	a(n)
1	1
2	2
3	4
4	7
5	3
6	8
7	14
8	5
9	12
10	20
11	6
12	16
13	27
14	9
15	21
16	34
17	10
18	25
19	41
20	11
21	28
22	47
23	13
24	33
25	54
26	15
27	37
28	60
29	17
30	42
31	68
32	18
33	45
34	73
35	19
36	48
37	79
38	22
39	55
40	23
41	58
42	94
43	24
44	61
45	99
46	26
47	66
48	107
49	29
50	71
51	115
52	30
53	75
54	121
55	31
56	78
57	126
58	32
59	81
60	132
61	35
62	87
63	140
64	36
65	91
66	147
67	38
68	96
69	155
70	39

[1, 2, 4, 7, 3, 8, 14, 5, 12, 20, 6, 16, 27, 9, 21, 34, 10, 25, 41, 11, 28, 47, 13, 33, 54, 15, 37, 60, 17, 42, 68, 18, 45, 73, 19, 48, 79, 22, 55, 23, 58, 94, 24, 61, 99, 26, 66, 107, 29, 71, 115, 30, 75, 121, 31, 78, 126, 32, 81, 132, 35, 87, 140, 36, 91, 147, 38, 96, 155, 39]

cp's OEIS Frontend

A081145 a(1)=1; thereafter, a(n) is the least positive integer which has not already occurred and is such that |a(n)-a(n-1)| is different from any |a(k)-a(k-1)| which has already occurred.

Table of values

List of values

n	a(n)
1	1
2	2
3	4
4	7
5	3
6	8
7	14
8	5
9	12
10	20
11	6
12	16
13	27
14	9
15	21
16	34
17	10
18	25
19	41
20	11
21	28
22	47
23	13
24	33
25	54
26	15
27	37
28	60
29	17
30	42
31	68
32	18
33	45
34	73
35	19
36	48
37	79
38	22
39	55
40	23
41	58
42	94
43	24
44	61
45	99
46	26
47	66
48	107
49	29
50	71
51	115
52	30
53	75
54	121
55	31
56	78
57	126
58	32
59	81
60	132
61	35
62	87
63	140
64	36
65	91
66	147
67	38
68	96
69	155
70	39

n	a(n)
1	1
2	2
3	4
4	7
5	3
6	8
7	14
8	5
9	12
10	20
11	6
12	16
13	27
14	9
15	21
16	34
17	10
18	25
19	41
20	11
21	28
22	47
23	13
24	33
25	54
26	15
27	37
28	60
29	17
30	42
31	68
32	18
33	45
34	73
35	19
36	48
37	79
38	22
39	55
40	23
41	58
42	94
43	24
44	61
45	99
46	26
47	66
48	107
49	29
50	71
51	115
52	30
53	75
54	121
55	31
56	78
57	126
58	32
59	81
60	132
61	35
62	87
63	140
64	36
65	91
66	147
67	38
68	96
69	155
70	39

n	a(n)
1	1
2	2
3	4
4	7
5	3
6	8
7	14
8	5
9	12
10	20
11	6
12	16
13	27
14	9
15	21
16	34
17	10
18	25
19	41
20	11
21	28
22	47
23	13
24	33
25	54
26	15
27	37
28	60
29	17
30	42
31	68
32	18
33	45
34	73
35	19
36	48
37	79
38	22
39	55
40	23
41	58
42	94
43	24
44	61
45	99
46	26
47	66
48	107
49	29
50	71
51	115
52	30
53	75
54	121
55	31
56	78
57	126
58	32
59	81
60	132
61	35
62	87
63	140
64	36
65	91
66	147
67	38
68	96
69	155
70	39