A239613 - cp's OEIS frontend

A239613 a(n) = Sum_{0 < x,y,z,t <= n and gcd(x^2 + y^2 + z^2 + t^2, n)=1} gcd(x^2 + y^2 + z^2 + t^2 - 1, n).

n	a(n)
1	1
2	16
3	96
4	384
5	960
6	1536
7	4032
8	8192
9	11664
10	15360
11	26400
12	36864
13	52416
14	64512
15	92160
16	163840
17	156672
18	186624
19	246240
20	368640
21	387072
22	422400
23	534336
24	786432
25	900000
26	838656
27	1259712
28	1548288
29	1364160
30	1474560
31	1785600
32	3145728

[1, 16, 96, 384, 960, 1536, 4032, 8192, 11664, 15360, 26400, 36864, 52416, 64512, 92160, 163840, 156672, 186624, 246240, 368640, 387072, 422400, 534336, 786432, 900000, 838656, 1259712, 1548288, 1364160, 1474560, 1785600, 3145728]

cp's OEIS Frontend

A239613 a(n) = Sum_{0 < x,y,z,t <= n and gcd(x^2 + y^2 + z^2 + t^2, n)=1} gcd(x^2 + y^2 + z^2 + t^2 - 1, n).

Table of values

List of values