A002135 - cp's OEIS frontend

A002135 Number of terms in a symmetrical determinant: a(n) = na(n-1) - (n-1)(n-2)*a(n-3)/2.

n	a(n)
0	1
1	1
2	2
3	5
4	17
5	73
6	388
7	2461
8	18155
9	152531
10	1436714
11	14986879
12	171453343
13	2134070335
14	28708008128
15	415017867707
16	6416208498137
17	105630583492969
18	1844908072865290
19	34071573484225549
20	663368639907213281
21	13580208904207073801

[1, 1, 2, 5, 17, 73, 388, 2461, 18155, 152531, 1436714, 14986879, 171453343, 2134070335, 28708008128, 415017867707, 6416208498137, 105630583492969, 1844908072865290, 34071573484225549, 663368639907213281, 13580208904207073801]

cp's OEIS Frontend

A002135 Number of terms in a symmetrical determinant: a(n) = na(n-1) - (n-1)(n-2)*a(n-3)/2.

Table of values

List of values

cp's OEIS Frontend

A002135 Number of terms in a symmetrical determinant: a(n) = n*a(n-1) - (n-1)*(n-2)*a(n-3)/2.

Table of values

List of values

A002135 Number of terms in a symmetrical determinant: a(n) = na(n-1) - (n-1)(n-2)*a(n-3)/2.