A036840 - cp's OEIS frontend

A036840 a(n) is the average of the repeating terms of {T(n,k)} rounded to the nearest integer (rounding up if there's a choice), if {T(n,k)} is eventually periodic; = 0 otherwise. Here T(n,k) is the "phi/sigma tug-of-war sequence with seed n" defined by T(n,1) = phi(n), T(n,2) = sigma(phi(n)), T(n,3) = phi(sigma(phi(n))), ..., T(n,k) = phi(T(n,k-1)) if k is odd and = sigma(T(n,k-1)) if k is even.

n	a(n)
1	1
2	1
3	3
4	3
5	7
6	3
7	7
8	7
9	7
10	7
11	7
12	7
13	20
14	7
15	12
16	12
17	39
18	7
19	39
20	12
21	20
22	7
23	20
24	12
25	20
26	20
27	39
28	20
29	39
30	12
31	39
32	39
33	20
34	39
35	39
36	20
37	154
38	39
39	39
40	39
41	39
42	20
43	154
44	20
45	39
46	20
47	39
48	39
49	154
50	20
51	154
52	39
53	154
54	39
55	39
56	39
57	154
58	39
59	39
60	39
61	100
62	39
63	154
64	154
65	100
66	20
67	100
68	154
69	39
70	39

[1, 1, 3, 3, 7, 3, 7, 7, 7, 7, 7, 7, 20, 7, 12, 12, 39, 7, 39, 12, 20, 7, 20, 12, 20, 20, 39, 20, 39, 12, 39, 39, 20, 39, 39, 20, 154, 39, 39, 39, 39, 20, 154, 20, 39, 20, 39, 39, 154, 20, 154, 39, 154, 39, 39, 39, 154, 39, 39, 39, 100, 39, 154, 154, 100, 20, 100, 154, 39, 39]

cp's OEIS Frontend

Table of values

List of values

n	a(n)
1	1
2	1
3	3
4	3
5	7
6	3
7	7
8	7
9	7
10	7
11	7
12	7
13	20
14	7
15	12
16	12
17	39
18	7
19	39
20	12
21	20
22	7
23	20
24	12
25	20
26	20
27	39
28	20
29	39
30	12
31	39
32	39
33	20
34	39
35	39
36	20
37	154
38	39
39	39
40	39
41	39
42	20
43	154
44	20
45	39
46	20
47	39
48	39
49	154
50	20
51	154
52	39
53	154
54	39
55	39
56	39
57	154
58	39
59	39
60	39
61	100
62	39
63	154
64	154
65	100
66	20
67	100
68	154
69	39
70	39

n	a(n)
1	1
2	1
3	3
4	3
5	7
6	3
7	7
8	7
9	7
10	7
11	7
12	7
13	20
14	7
15	12
16	12
17	39
18	7
19	39
20	12
21	20
22	7
23	20
24	12
25	20
26	20
27	39
28	20
29	39
30	12
31	39
32	39
33	20
34	39
35	39
36	20
37	154
38	39
39	39
40	39
41	39
42	20
43	154
44	20
45	39
46	20
47	39
48	39
49	154
50	20
51	154
52	39
53	154
54	39
55	39
56	39
57	154
58	39
59	39
60	39
61	100
62	39
63	154
64	154
65	100
66	20
67	100
68	154
69	39
70	39

n	a(n)
1	1
2	1
3	3
4	3
5	7
6	3
7	7
8	7
9	7
10	7
11	7
12	7
13	20
14	7
15	12
16	12
17	39
18	7
19	39
20	12
21	20
22	7
23	20
24	12
25	20
26	20
27	39
28	20
29	39
30	12
31	39
32	39
33	20
34	39
35	39
36	20
37	154
38	39
39	39
40	39
41	39
42	20
43	154
44	20
45	39
46	20
47	39
48	39
49	154
50	20
51	154
52	39
53	154
54	39
55	39
56	39
57	154
58	39
59	39
60	39
61	100
62	39
63	154
64	154
65	100
66	20
67	100
68	154
69	39
70	39