A130767 - cp's OEIS frontend

A130767 a(n) = product{k=1 to n} (k-th integer from among those positive integers which are coprime to (n+1-k)).

n	a(n)
1	1
2	2
3	9
4	40
5	420
6	2700
7	56595
8	419328
9	8820900
10	88488400
11	2327925600
12	38767286880
13	1912404574080
14	21612951360000
15	644047087612500
16	10985391056640000
17	634391869996684800
18	14046187624838328960
19	764077915447610400000
20	15840110879873280000000
21	755098009918296312668400

[1, 2, 9, 40, 420, 2700, 56595, 419328, 8820900, 88488400, 2327925600, 38767286880, 1912404574080, 21612951360000, 644047087612500, 10985391056640000, 634391869996684800, 14046187624838328960, 764077915447610400000, 15840110879873280000000, 755098009918296312668400]

cp's OEIS Frontend

A130767 a(n) = product{k=1 to n} (k-th integer from among those positive integers which are coprime to (n+1-k)).

Table of values

List of values