A320541 - cp's OEIS frontend

A320541 Triangle read by rows: T(n,k) (1<=k<=n) = Sum_{i=1..n, j=1..k, gcd(i,j)=1} (n+1-i)*(k+1-j).

n	a(n)
1	1
2	3
3	8
4	6
5	16
6	31
7	10
8	26
9	50
10	80
11	15
12	39
13	75
14	120
15	179
16	21
17	54
18	103
19	164
20	244
21	332
22	28
23	72
24	137
25	218
26	324
27	441
28	585
29	36
30	92
31	175
32	278
33	413
34	562
35	745
36	948
37	45
38	115
39	218
40	346
41	514
42	699
43	926
44	1178
45	1463
46	55
47	140
48	265
49	420
50	623
51	846
52	1120
53	1424
54	1768
55	2136

[1, 3, 8, 6, 16, 31, 10, 26, 50, 80, 15, 39, 75, 120, 179, 21, 54, 103, 164, 244, 332, 28, 72, 137, 218, 324, 441, 585, 36, 92, 175, 278, 413, 562, 745, 948, 45, 115, 218, 346, 514, 699, 926, 1178, 1463, 55, 140, 265, 420, 623, 846, 1120, 1424, 1768, 2136]

cp's OEIS Frontend

A320541 Triangle read by rows: T(n,k) (1<=k<=n) = Sum_{i=1..n, j=1..k, gcd(i,j)=1} (n+1-i)*(k+1-j).

Table of values

List of values