A045761 - cp's OEIS frontend

A045761 Define polynomials Pn by P0 = 0, P1 = x, P2 = P1 + P0, P3 = P2 * P1, P4 = P3 + P2, etc. alternately adding or multiplying. For even n > 2k, then first k coefficients of Pn remain unchanged and their values are the first k terms of the sequence.

n	a(n)
0	0
1	1
2	1
3	1
4	2
5	3
6	6
7	12
8	24
9	50
10	107
11	232
12	508
13	1124
14	2513
15	5665
16	12858
17	29356
18	67371
19	155345
20	359733
21	836261
22	1950829
23	4565305
24	10714501
25	25212843
26	59474318
27	140609809
28	333126672
29	790764280
30	1880489541
31	4479494059
32	10687448937
33	25536624382
34	61102431113

[0, 1, 1, 1, 2, 3, 6, 12, 24, 50, 107, 232, 508, 1124, 2513, 5665, 12858, 29356, 67371, 155345, 359733, 836261, 1950829, 4565305, 10714501, 25212843, 59474318, 140609809, 333126672, 790764280, 1880489541, 4479494059, 10687448937, 25536624382, 61102431113]

cp's OEIS Frontend

A045761 Define polynomials Pn by P0 = 0, P1 = x, P2 = P1 + P0, P3 = P2 * P1, P4 = P3 + P2, etc. alternately adding or multiplying. For even n > 2k, then first k coefficients of Pn remain unchanged and their values are the first k terms of the sequence.

Table of values

List of values