A190122 - cp's OEIS frontend

A190122 a(n) = Sum_{k=1..n} k*lcm(k,k')/gcd(k,k'), where k' is arithmetic derivative of k.

n	a(n)
1	0
2	4
3	13
4	17
5	42
6	222
7	271
8	319
9	373
10	1073
11	1194
12	1338
13	1507
14	3271
15	5071
16	5103
17	5392
18	6148
19	6509
20	7109
21	11519
22	17811
23	18340
24	19924
25	20174
26	30314
27	30341
28	31909
29	32750
30	60650
31	61611
32	61931
33	77177
34	99141
35	113841
36	114381
37	115750
38	146074
39	170410
40	177210
41	178891

[0, 4, 13, 17, 42, 222, 271, 319, 373, 1073, 1194, 1338, 1507, 3271, 5071, 5103, 5392, 6148, 6509, 7109, 11519, 17811, 18340, 19924, 20174, 30314, 30341, 31909, 32750, 60650, 61611, 61931, 77177, 99141, 113841, 114381, 115750, 146074, 170410, 177210, 178891]

cp's OEIS Frontend

A190122 a(n) = Sum_{k=1..n} k*lcm(k,k')/gcd(k,k'), where k' is arithmetic derivative of k.

Table of values

List of values