A008953 - cp's OEIS frontend

A008953 a(n) is the leading digit of the n-th triangular number, n*(n+1)/2.

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

[1, 3, 6, 1, 1, 2, 2, 3, 4, 5, 6, 7, 9, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 6, 6, 7, 7, 7, 8, 8, 9, 9, 9, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4]

cp's OEIS Frontend

A008953 a(n) is the leading digit of the n-th triangular number, n*(n+1)/2.

Table of values

List of values

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

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

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