A005409 - cp's OEIS frontend

A005409 Number of polynomials of height n: a(1)=1, a(2)=1, a(3)=4, a(n) = 2*a(n-1) + a(n-2) + 2 for n >= 4.

n	a(n)
1	1
2	1
3	4
4	11
5	28
6	69
7	168
8	407
9	984
10	2377
11	5740
12	13859
13	33460
14	80781
15	195024
16	470831
17	1136688
18	2744209
19	6625108
20	15994427
21	38613964
22	93222357
23	225058680
24	543339719
25	1311738120
26	3166815961
27	7645370044
28	18457556051
29	44560482148
30	107578520349
31	259717522848

[1, 1, 4, 11, 28, 69, 168, 407, 984, 2377, 5740, 13859, 33460, 80781, 195024, 470831, 1136688, 2744209, 6625108, 15994427, 38613964, 93222357, 225058680, 543339719, 1311738120, 3166815961, 7645370044, 18457556051, 44560482148, 107578520349, 259717522848]

cp's OEIS Frontend

A005409 Number of polynomials of height n: a(1)=1, a(2)=1, a(3)=4, a(n) = 2*a(n-1) + a(n-2) + 2 for n >= 4.

Table of values

List of values