A330319 - cp's OEIS frontend

A330319 a(n) = Sum_{i=1..n} phi(i)*phi(i+1), where phi(n) = A000010(n) is Euler's totient function.

n	a(n)
1	1
2	3
3	7
4	15
5	23
6	35
7	59
8	83
9	107
10	147
11	187
12	235
13	307
14	355
15	419
16	547
17	643
18	751
19	895
20	991
21	1111
22	1331
23	1507
24	1667
25	1907
26	2123
27	2339
28	2675
29	2899
30	3139
31	3619
32	3939
33	4259
34	4643
35	4931
36	5363
37	6011
38	6443
39	6827
40	7467
41	7947
42	8451
43	9291
44	9771
45	10299
46	11311
47	12047
48	12719
49	13559
50	14199
51	14967
52	16215
53	17151
54	17871
55	18831

[1, 3, 7, 15, 23, 35, 59, 83, 107, 147, 187, 235, 307, 355, 419, 547, 643, 751, 895, 991, 1111, 1331, 1507, 1667, 1907, 2123, 2339, 2675, 2899, 3139, 3619, 3939, 4259, 4643, 4931, 5363, 6011, 6443, 6827, 7467, 7947, 8451, 9291, 9771, 10299, 11311, 12047, 12719, 13559, 14199, 14967, 16215, 17151, 17871, 18831]

cp's OEIS Frontend

A330319 a(n) = Sum_{i=1..n} phi(i)*phi(i+1), where phi(n) = A000010(n) is Euler's totient function.

Table of values

List of values