A063423 - cp's OEIS frontend

A063423 a(1) = 9, a(n) = concatenation of two closest factors of a(n-1) whose product equals a(n-1) or if a(n-1) is a prime then the concatenation of 1 and a(n-1).

n	a(n)
1	9
2	33
3	311
4	1311
5	2357
6	12357
7	91373
8	191373
9	273701
10	594639
11	966071
12	3792549
13	7714919
14	18474177
15	36158059
16	217166627
17	415296747
18	1269327263
19	8581147923
20	85531003291
21	307572780863
22	417501775143
23	594709702027
24	1334471501519

[9, 33, 311, 1311, 2357, 12357, 91373, 191373, 273701, 594639, 966071, 3792549, 7714919, 18474177, 36158059, 217166627, 415296747, 1269327263, 8581147923, 85531003291, 307572780863, 417501775143, 594709702027, 1334471501519]

cp's OEIS Frontend

A063423 a(1) = 9, a(n) = concatenation of two closest factors of a(n-1) whose product equals a(n-1) or if a(n-1) is a prime then the concatenation of 1 and a(n-1).

Table of values

List of values