A377226 - cp's OEIS frontend

A377226 Take the sequence of the signed denominators of Leibniz series for Pi/4 (cf. A157142) and permute the terms so that a negative term follows every two positive terms and the absolute difference between two consecutive terms of the same sign is 4.

n	a(n)
0	1
1	5
2	-3
3	9
4	13
5	-7
6	17
7	21
8	-11
9	25
10	29
11	-15
12	33
13	37
14	-19
15	41
16	45
17	-23
18	49
19	53
20	-27
21	57
22	61
23	-31
24	65
25	69
26	-35
27	73
28	77
29	-39
30	81
31	85
32	-43
33	89
34	93
35	-47
36	97
37	101
38	-51
39	105
40	109
41	-55
42	113
43	117
44	-59
45	121
46	125
47	-63
48	129
49	133
50	-67
51	137
52	141
53	-71
54	145
55	149
56	-75
57	153
58	157
59	-79
60	161

[1, 5, -3, 9, 13, -7, 17, 21, -11, 25, 29, -15, 33, 37, -19, 41, 45, -23, 49, 53, -27, 57, 61, -31, 65, 69, -35, 73, 77, -39, 81, 85, -43, 89, 93, -47, 97, 101, -51, 105, 109, -55, 113, 117, -59, 121, 125, -63, 129, 133, -67, 137, 141, -71, 145, 149, -75, 153, 157, -79, 161]

cp's OEIS Frontend

A377226 Take the sequence of the signed denominators of Leibniz series for Pi/4 (cf. A157142) and permute the terms so that a negative term follows every two positive terms and the absolute difference between two consecutive terms of the same sign is 4.

Table of values

List of values

n	a(n)
0	1
1	5
2	-3
3	9
4	13
5	-7
6	17
7	21
8	-11
9	25
10	29
11	-15
12	33
13	37
14	-19
15	41
16	45
17	-23
18	49
19	53
20	-27
21	57
22	61
23	-31
24	65
25	69
26	-35
27	73
28	77
29	-39
30	81
31	85
32	-43
33	89
34	93
35	-47
36	97
37	101
38	-51
39	105
40	109
41	-55
42	113
43	117
44	-59
45	121
46	125
47	-63
48	129
49	133
50	-67
51	137
52	141
53	-71
54	145
55	149
56	-75
57	153
58	157
59	-79
60	161

n	a(n)
0	1
1	5
2	-3
3	9
4	13
5	-7
6	17
7	21
8	-11
9	25
10	29
11	-15
12	33
13	37
14	-19
15	41
16	45
17	-23
18	49
19	53
20	-27
21	57
22	61
23	-31
24	65
25	69
26	-35
27	73
28	77
29	-39
30	81
31	85
32	-43
33	89
34	93
35	-47
36	97
37	101
38	-51
39	105
40	109
41	-55
42	113
43	117
44	-59
45	121
46	125
47	-63
48	129
49	133
50	-67
51	137
52	141
53	-71
54	145
55	149
56	-75
57	153
58	157
59	-79
60	161

n	a(n)
0	1
1	5
2	-3
3	9
4	13
5	-7
6	17
7	21
8	-11
9	25
10	29
11	-15
12	33
13	37
14	-19
15	41
16	45
17	-23
18	49
19	53
20	-27
21	57
22	61
23	-31
24	65
25	69
26	-35
27	73
28	77
29	-39
30	81
31	85
32	-43
33	89
34	93
35	-47
36	97
37	101
38	-51
39	105
40	109
41	-55
42	113
43	117
44	-59
45	121
46	125
47	-63
48	129
49	133
50	-67
51	137
52	141
53	-71
54	145
55	149
56	-75
57	153
58	157
59	-79
60	161