A254593 - cp's OEIS frontend

A254593 a(n) = (3/n^3) * Sum_{d|n} (-1)^(n+d)moebius(n/d)binomial(2*d,d).

n	a(n)
1	6
2	3
3	2
4	3
5	6
6	13
7	30
8	75
9	200
10	555
11	1590
12	4693
13	14202
14	43863
15	137882
16	440235
17	1424958
18	4668304
19	15459366
20	51692379
21	174362770
22	592815459
23	2030105382
24	6998177293
25	24270836436
26	84646997613
27	296744311172
28	1045283877639
29	3698462401026
30	13140509079977
31	46869358523238
32	167781751129899

[6, 3, 2, 3, 6, 13, 30, 75, 200, 555, 1590, 4693, 14202, 43863, 137882, 440235, 1424958, 4668304, 15459366, 51692379, 174362770, 592815459, 2030105382, 6998177293, 24270836436, 84646997613, 296744311172, 1045283877639, 3698462401026, 13140509079977, 46869358523238, 167781751129899]

cp's OEIS Frontend

A254593 a(n) = (3/n^3) * Sum_{d|n} (-1)^(n+d)moebius(n/d)binomial(2*d,d).

Table of values

List of values

cp's OEIS Frontend

A254593 a(n) = (3/n^3) * Sum_{d|n} (-1)^(n+d)*moebius(n/d)*binomial(2*d,d).

Table of values

List of values

A254593 a(n) = (3/n^3) * Sum_{d|n} (-1)^(n+d)moebius(n/d)binomial(2*d,d).