A331761 - cp's OEIS frontend

A331761 a(n) = Sum_{i=1..n, j=1..n, gcd(i,j)=2} (n+1-i)*(n+1-j).

n	a(n)
1	0
2	1
3	4
4	15
5	32
6	71
7	124
8	211
9	320
10	499
11	716
12	999
13	1328
14	1799
15	2340
16	3023
17	3792
18	4767
19	5852
20	7135
21	8544
22	10319
23	12260
24	14471
25	16864
26	19775
27	22916
28	26467
29	30272
30	34587
31	39188
32	44347
33	49824
34	56195
35	62948
36	70311
37	78080
38	86975

[0, 1, 4, 15, 32, 71, 124, 211, 320, 499, 716, 999, 1328, 1799, 2340, 3023, 3792, 4767, 5852, 7135, 8544, 10319, 12260, 14471, 16864, 19775, 22916, 26467, 30272, 34587, 39188, 44347, 49824, 56195, 62948, 70311, 78080, 86975]

cp's OEIS Frontend

A331761 a(n) = Sum_{i=1..n, j=1..n, gcd(i,j)=2} (n+1-i)*(n+1-j).

Table of values

List of values