A132668 - cp's OEIS frontend

A132668 a(1)=1, a(n) = 4*a(n-1) if the minimal positive integer not yet in the sequence is greater than a(n-1), else a(n) = a(n-1) - 1.

n	a(n)
1	1
2	4
3	3
4	2
5	8
6	7
7	6
8	5
9	20
10	19
11	18
12	17
13	16
14	15
15	14
16	13
17	12
18	11
19	10
20	9
21	36
22	35
23	34
24	33
25	32
26	31
27	30
28	29
29	28
30	27
31	26
32	25
33	24
34	23
35	22
36	21
37	84
38	83
39	82
40	81
41	80
42	79
43	78
44	77
45	76
46	75
47	74
48	73
49	72
50	71
51	70
52	69
53	68
54	67
55	66
56	65
57	64
58	63
59	62
60	61
61	60
62	59
63	58
64	57
65	56
66	55
67	54
68	53
69	52
70	51
71	50
72	49

[1, 4, 3, 2, 8, 7, 6, 5, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 36, 35, 34, 33, 32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 84, 83, 82, 81, 80, 79, 78, 77, 76, 75, 74, 73, 72, 71, 70, 69, 68, 67, 66, 65, 64, 63, 62, 61, 60, 59, 58, 57, 56, 55, 54, 53, 52, 51, 50, 49]

cp's OEIS Frontend

A132668 a(1)=1, a(n) = 4*a(n-1) if the minimal positive integer not yet in the sequence is greater than a(n-1), else a(n) = a(n-1) - 1.

Table of values

List of values

n	a(n)
1	1
2	4
3	3
4	2
5	8
6	7
7	6
8	5
9	20
10	19
11	18
12	17
13	16
14	15
15	14
16	13
17	12
18	11
19	10
20	9
21	36
22	35
23	34
24	33
25	32
26	31
27	30
28	29
29	28
30	27
31	26
32	25
33	24
34	23
35	22
36	21
37	84
38	83
39	82
40	81
41	80
42	79
43	78
44	77
45	76
46	75
47	74
48	73
49	72
50	71
51	70
52	69
53	68
54	67
55	66
56	65
57	64
58	63
59	62
60	61
61	60
62	59
63	58
64	57
65	56
66	55
67	54
68	53
69	52
70	51
71	50
72	49

n	a(n)
1	1
2	4
3	3
4	2
5	8
6	7
7	6
8	5
9	20
10	19
11	18
12	17
13	16
14	15
15	14
16	13
17	12
18	11
19	10
20	9
21	36
22	35
23	34
24	33
25	32
26	31
27	30
28	29
29	28
30	27
31	26
32	25
33	24
34	23
35	22
36	21
37	84
38	83
39	82
40	81
41	80
42	79
43	78
44	77
45	76
46	75
47	74
48	73
49	72
50	71
51	70
52	69
53	68
54	67
55	66
56	65
57	64
58	63
59	62
60	61
61	60
62	59
63	58
64	57
65	56
66	55
67	54
68	53
69	52
70	51
71	50
72	49

n	a(n)
1	1
2	4
3	3
4	2
5	8
6	7
7	6
8	5
9	20
10	19
11	18
12	17
13	16
14	15
15	14
16	13
17	12
18	11
19	10
20	9
21	36
22	35
23	34
24	33
25	32
26	31
27	30
28	29
29	28
30	27
31	26
32	25
33	24
34	23
35	22
36	21
37	84
38	83
39	82
40	81
41	80
42	79
43	78
44	77
45	76
46	75
47	74
48	73
49	72
50	71
51	70
52	69
53	68
54	67
55	66
56	65
57	64
58	63
59	62
60	61
61	60
62	59
63	58
64	57
65	56
66	55
67	54
68	53
69	52
70	51
71	50
72	49