A102640 - cp's OEIS frontend

A102640 Compute the greatest prime factors (GPFs, A006530()) of j + 2^n for j = 0, 1, ..., L. a(n) is the maximal length L of such a sequence in which the greatest prime factors are increasing with increasing j.

n	a(n)
1	2
2	2
3	4
4	2
5	3
6	2
7	2
8	2
9	3
10	2
11	2
12	4
13	2
14	3
15	2
16	2
17	3
18	4
19	2
20	3
21	3
22	6
23	2
24	3
25	2
26	4
27	2
28	2
29	3
30	4
31	2
32	3
33	3
34	2
35	2
36	4
37	2
38	4
39	2
40	2
41	2
42	4
43	2
44	3
45	4
46	4
47	2
48	4
49	2
50	3
51	3
52	2
53	2
54	3
55	2
56	2
57	3
58	2
59	2
60	2
61	2
62	3
63	2
64	2
65	3
66	4
67	2
68	3
69	4
70	4
71	2
72	4
73	2
74	3
75	2
76	2
77	4
78	4
79	2
80	3
81	3
82	4
83	2
84	2
85	2
86	3
87	2
88	4
89	2
90	3
91	2
92	2
93	3
94	2
95	2
96	2
97	3
98	4
99	2
100	4
101	2
102	3
103	2
104	2
105	3

[2, 2, 4, 2, 3, 2, 2, 2, 3, 2, 2, 4, 2, 3, 2, 2, 3, 4, 2, 3, 3, 6, 2, 3, 2, 4, 2, 2, 3, 4, 2, 3, 3, 2, 2, 4, 2, 4, 2, 2, 2, 4, 2, 3, 4, 4, 2, 4, 2, 3, 3, 2, 2, 3, 2, 2, 3, 2, 2, 2, 2, 3, 2, 2, 3, 4, 2, 3, 4, 4, 2, 4, 2, 3, 2, 2, 4, 4, 2, 3, 3, 4, 2, 2, 2, 3, 2, 4, 2, 3, 2, 2, 3, 2, 2, 2, 3, 4, 2, 4, 2, 3, 2, 2, 3]

cp's OEIS Frontend

A102640 Compute the greatest prime factors (GPFs, A006530()) of j + 2^n for j = 0, 1, ..., L. a(n) is the maximal length L of such a sequence in which the greatest prime factors are increasing with increasing j.

Table of values

List of values

n	a(n)
1	2
2	2
3	4
4	2
5	3
6	2
7	2
8	2
9	3
10	2
11	2
12	4
13	2
14	3
15	2
16	2
17	3
18	4
19	2
20	3
21	3
22	6
23	2
24	3
25	2
26	4
27	2
28	2
29	3
30	4
31	2
32	3
33	3
34	2
35	2
36	4
37	2
38	4
39	2
40	2
41	2
42	4
43	2
44	3
45	4
46	4
47	2
48	4
49	2
50	3
51	3
52	2
53	2
54	3
55	2
56	2
57	3
58	2
59	2
60	2
61	2
62	3
63	2
64	2
65	3
66	4
67	2
68	3
69	4
70	4
71	2
72	4
73	2
74	3
75	2
76	2
77	4
78	4
79	2
80	3
81	3
82	4
83	2
84	2
85	2
86	3
87	2
88	4
89	2
90	3
91	2
92	2
93	3
94	2
95	2
96	2
97	3
98	4
99	2
100	4
101	2
102	3
103	2
104	2
105	3

n	a(n)
1	2
2	2
3	4
4	2
5	3
6	2
7	2
8	2
9	3
10	2
11	2
12	4
13	2
14	3
15	2
16	2
17	3
18	4
19	2
20	3
21	3
22	6
23	2
24	3
25	2
26	4
27	2
28	2
29	3
30	4
31	2
32	3
33	3
34	2
35	2
36	4
37	2
38	4
39	2
40	2
41	2
42	4
43	2
44	3
45	4
46	4
47	2
48	4
49	2
50	3
51	3
52	2
53	2
54	3
55	2
56	2
57	3
58	2
59	2
60	2
61	2
62	3
63	2
64	2
65	3
66	4
67	2
68	3
69	4
70	4
71	2
72	4
73	2
74	3
75	2
76	2
77	4
78	4
79	2
80	3
81	3
82	4
83	2
84	2
85	2
86	3
87	2
88	4
89	2
90	3
91	2
92	2
93	3
94	2
95	2
96	2
97	3
98	4
99	2
100	4
101	2
102	3
103	2
104	2
105	3

n	a(n)
1	2
2	2
3	4
4	2
5	3
6	2
7	2
8	2
9	3
10	2
11	2
12	4
13	2
14	3
15	2
16	2
17	3
18	4
19	2
20	3
21	3
22	6
23	2
24	3
25	2
26	4
27	2
28	2
29	3
30	4
31	2
32	3
33	3
34	2
35	2
36	4
37	2
38	4
39	2
40	2
41	2
42	4
43	2
44	3
45	4
46	4
47	2
48	4
49	2
50	3
51	3
52	2
53	2
54	3
55	2
56	2
57	3
58	2
59	2
60	2
61	2
62	3
63	2
64	2
65	3
66	4
67	2
68	3
69	4
70	4
71	2
72	4
73	2
74	3
75	2
76	2
77	4
78	4
79	2
80	3
81	3
82	4
83	2
84	2
85	2
86	3
87	2
88	4
89	2
90	3
91	2
92	2
93	3
94	2
95	2
96	2
97	3
98	4
99	2
100	4
101	2
102	3
103	2
104	2
105	3