A209674 - cp's OEIS frontend

A209674 For each n, define a sequence of numbers by S(0)=n, S(i) = sum of last two digits of the concatenation S(0)S(1)S(2)...S(i-1); a(n) = smallest m such that S(m) = 5, or -1 if 5 is never reached.

n	a(n)
0	-1
1	4
2	9
3	9
4	5
5	0
6	4
7	3
8	10
9	11
10	5
11	3
12	2
13	6
14	1
15	5
16	8
17	7
18	9
19	6
20	10
21	7
22	8
23	1
24	7
25	4
26	3
27	10
28	6
29	4
30	10
31	2
32	1
33	8
34	5
35	8
36	7
37	6
38	4
39	3
40	6
41	1
42	4
43	7
44	4
45	3
46	6
47	4
48	3
49	7
50	1
51	9
52	11
53	5
54	8
55	6
56	4
57	3
58	7
59	2
60	5
61	8
62	7
63	4
64	6
65	4
66	3
67	7
68	2
69	6
70	4
71	10
72	5
73	6
74	4
75	3
76	7
77	2
78	6
79	9
80	11
81	7
82	6
83	4
84	3
85	7
86	2
87	6
88	9
89	8
90	12
91	6
92	4
93	3
94	7
95	2
96	6
97	9
98	8
99	10

[-1, 4, 9, 9, 5, 0, 4, 3, 10, 11, 5, 3, 2, 6, 1, 5, 8, 7, 9, 6, 10, 7, 8, 1, 7, 4, 3, 10, 6, 4, 10, 2, 1, 8, 5, 8, 7, 6, 4, 3, 6, 1, 4, 7, 4, 3, 6, 4, 3, 7, 1, 9, 11, 5, 8, 6, 4, 3, 7, 2, 5, 8, 7, 4, 6, 4, 3, 7, 2, 6, 4, 10, 5, 6, 4, 3, 7, 2, 6, 9, 11, 7, 6, 4, 3, 7, 2, 6, 9, 8, 12, 6, 4, 3, 7, 2, 6, 9, 8, 10]

cp's OEIS Frontend

A209674 For each n, define a sequence of numbers by S(0)=n, S(i) = sum of last two digits of the concatenation S(0)S(1)S(2)...S(i-1); a(n) = smallest m such that S(m) = 5, or -1 if 5 is never reached.

Table of values

List of values

n	a(n)
0	-1
1	4
2	9
3	9
4	5
5	0
6	4
7	3
8	10
9	11
10	5
11	3
12	2
13	6
14	1
15	5
16	8
17	7
18	9
19	6
20	10
21	7
22	8
23	1
24	7
25	4
26	3
27	10
28	6
29	4
30	10
31	2
32	1
33	8
34	5
35	8
36	7
37	6
38	4
39	3
40	6
41	1
42	4
43	7
44	4
45	3
46	6
47	4
48	3
49	7
50	1
51	9
52	11
53	5
54	8
55	6
56	4
57	3
58	7
59	2
60	5
61	8
62	7
63	4
64	6
65	4
66	3
67	7
68	2
69	6
70	4
71	10
72	5
73	6
74	4
75	3
76	7
77	2
78	6
79	9
80	11
81	7
82	6
83	4
84	3
85	7
86	2
87	6
88	9
89	8
90	12
91	6
92	4
93	3
94	7
95	2
96	6
97	9
98	8
99	10

n	a(n)
0	-1
1	4
2	9
3	9
4	5
5	0
6	4
7	3
8	10
9	11
10	5
11	3
12	2
13	6
14	1
15	5
16	8
17	7
18	9
19	6
20	10
21	7
22	8
23	1
24	7
25	4
26	3
27	10
28	6
29	4
30	10
31	2
32	1
33	8
34	5
35	8
36	7
37	6
38	4
39	3
40	6
41	1
42	4
43	7
44	4
45	3
46	6
47	4
48	3
49	7
50	1
51	9
52	11
53	5
54	8
55	6
56	4
57	3
58	7
59	2
60	5
61	8
62	7
63	4
64	6
65	4
66	3
67	7
68	2
69	6
70	4
71	10
72	5
73	6
74	4
75	3
76	7
77	2
78	6
79	9
80	11
81	7
82	6
83	4
84	3
85	7
86	2
87	6
88	9
89	8
90	12
91	6
92	4
93	3
94	7
95	2
96	6
97	9
98	8
99	10

n	a(n)
0	-1
1	4
2	9
3	9
4	5
5	0
6	4
7	3
8	10
9	11
10	5
11	3
12	2
13	6
14	1
15	5
16	8
17	7
18	9
19	6
20	10
21	7
22	8
23	1
24	7
25	4
26	3
27	10
28	6
29	4
30	10
31	2
32	1
33	8
34	5
35	8
36	7
37	6
38	4
39	3
40	6
41	1
42	4
43	7
44	4
45	3
46	6
47	4
48	3
49	7
50	1
51	9
52	11
53	5
54	8
55	6
56	4
57	3
58	7
59	2
60	5
61	8
62	7
63	4
64	6
65	4
66	3
67	7
68	2
69	6
70	4
71	10
72	5
73	6
74	4
75	3
76	7
77	2
78	6
79	9
80	11
81	7
82	6
83	4
84	3
85	7
86	2
87	6
88	9
89	8
90	12
91	6
92	4
93	3
94	7
95	2
96	6
97	9
98	8
99	10