A118255 - cp's OEIS frontend

A118255 a(1)=1, then a(n)=2a(n-1) if n is prime, a(n)=2a(n-1)+1 if n not prime.

n	a(n)
1	1
2	2
3	4
4	9
5	18
6	37
7	74
8	149
9	299
10	599
11	1198
12	2397
13	4794
14	9589
15	19179
16	38359
17	76718
18	153437
19	306874
20	613749
21	1227499
22	2454999
23	4909998
24	9819997
25	19639995
26	39279991
27	78559983
28	157119967
29	314239934
30	628479869
31	1256959738
32	2513919477
33	5027838955
34	10055677911

[1, 2, 4, 9, 18, 37, 74, 149, 299, 599, 1198, 2397, 4794, 9589, 19179, 38359, 76718, 153437, 306874, 613749, 1227499, 2454999, 4909998, 9819997, 19639995, 39279991, 78559983, 157119967, 314239934, 628479869, 1256959738, 2513919477, 5027838955, 10055677911]

cp's OEIS Frontend

A118255 a(1)=1, then a(n)=2a(n-1) if n is prime, a(n)=2a(n-1)+1 if n not prime.

Table of values

List of values

cp's OEIS Frontend

A118255 a(1)=1, then a(n)=2*a(n-1) if n is prime, a(n)=2*a(n-1)+1 if n not prime.

Table of values

List of values

A118255 a(1)=1, then a(n)=2a(n-1) if n is prime, a(n)=2a(n-1)+1 if n not prime.