A369580 - cp's OEIS frontend

A369580 a(n) := f(n, n), where f(0,0) = 1/3, f(0,k) = 0 and f(k,0) = 3^(k-1) if k > 0, and f(n, m) = f(n, m-1) + f(n-1, m) + 3*f(n-1, m-1) otherwise.

n	a(n)
1	2
2	16
3	138
4	1216
5	10802
6	96336
7	861114
8	7708416
9	69072354
10	619380496
11	5557080938
12	49879087296
13	447852531986
14	4022246329936
15	36132550233498
16	324645166734336
17	2917340834679234
18	26219438520320016
19	235672871308226634
20	2118552629658530496
21	19046140604787232242
22	171241206828437556816

[2, 16, 138, 1216, 10802, 96336, 861114, 7708416, 69072354, 619380496, 5557080938, 49879087296, 447852531986, 4022246329936, 36132550233498, 324645166734336, 2917340834679234, 26219438520320016, 235672871308226634, 2118552629658530496, 19046140604787232242, 171241206828437556816]

cp's OEIS Frontend

A369580 a(n) := f(n, n), where f(0,0) = 1/3, f(0,k) = 0 and f(k,0) = 3^(k-1) if k > 0, and f(n, m) = f(n, m-1) + f(n-1, m) + 3*f(n-1, m-1) otherwise.

Table of values

List of values