A049690 - cp's OEIS frontend

A049690 a(n) = Sum_{k=1..n} phi(2*k), where phi = Euler totient function, cf. A000010.

n	a(n)
0	0
1	1
2	3
3	5
4	9
5	13
6	17
7	23
8	31
9	37
10	45
11	55
12	63
13	75
14	87
15	95
16	111
17	127
18	139
19	157
20	173
21	185
22	205
23	227
24	243
25	263
26	287
27	305
28	329
29	357
30	373
31	403
32	435
33	455
34	487
35	511
36	535
37	571
38	607
39	631
40	663
41	703
42	727
43	769
44	809
45	833
46	877
47	923
48	955
49	997
50	1037
51	1069
52	1117
53	1169
54	1205

[0, 1, 3, 5, 9, 13, 17, 23, 31, 37, 45, 55, 63, 75, 87, 95, 111, 127, 139, 157, 173, 185, 205, 227, 243, 263, 287, 305, 329, 357, 373, 403, 435, 455, 487, 511, 535, 571, 607, 631, 663, 703, 727, 769, 809, 833, 877, 923, 955, 997, 1037, 1069, 1117, 1169, 1205]

cp's OEIS Frontend

A049690 a(n) = Sum_{k=1..n} phi(2*k), where phi = Euler totient function, cf. A000010.

Table of values

List of values