A049920 - cp's OEIS frontend

A049920 a(n) = a(1) + a(2) + ... + a(n-1) - a(m) for n >= 4, where m = 2*n - 3 - 2^(p+1) and p is the unique integer such that 2^p < n-1 <= 2^(p+1), with a(1) = 1, a(2) = 3, and a(3) = 2.

n	a(n)
1	1
2	3
3	2
4	5
5	9
6	19
7	37
8	67
9	106
10	248
11	495
12	983
13	1938
14	3807
15	7225
16	13007
17	20727
18	48678
19	97355
20	194703
21	389378
22	778687
23	1556985
24	3112527
25	6219767
26	12426032
27	24775436
28	49258849
29	97350091
30	190037400
31	361519131
32	650463607
33	1036758174

[1, 3, 2, 5, 9, 19, 37, 67, 106, 248, 495, 983, 1938, 3807, 7225, 13007, 20727, 48678, 97355, 194703, 389378, 778687, 1556985, 3112527, 6219767, 12426032, 24775436, 49258849, 97350091, 190037400, 361519131, 650463607, 1036758174]

cp's OEIS Frontend

A049920 a(n) = a(1) + a(2) + ... + a(n-1) - a(m) for n >= 4, where m = 2*n - 3 - 2^(p+1) and p is the unique integer such that 2^p < n-1 <= 2^(p+1), with a(1) = 1, a(2) = 3, and a(3) = 2.

Table of values

List of values