A014533 - cp's OEIS frontend

A014533 Form array in which n-th row is obtained by expanding (1 + x + x^2)^n and taking the 4th column from the center.

n	a(n)
1	1
2	5
3	21
4	77
5	266
6	882
7	2850
8	9042
9	28314
10	87802
11	270270
12	827190
13	2520336
14	7651632
15	23162976
16	69954048
17	210859245
18	634569201
19	1907165337
20	5725520801
21	17172595110
22	51465297950
23	154135675070
24	461366154990
25	1380317174145

[1, 5, 21, 77, 266, 882, 2850, 9042, 28314, 87802, 270270, 827190, 2520336, 7651632, 23162976, 69954048, 210859245, 634569201, 1907165337, 5725520801, 17172595110, 51465297950, 154135675070, 461366154990, 1380317174145]

cp's OEIS Frontend

A014533 Form array in which n-th row is obtained by expanding (1 + x + x^2)^n and taking the 4th column from the center.

Table of values

List of values