A099151 - cp's OEIS frontend

A099151 Positive integers a such that f(3a)+f(a)=concatenation of 3a and a, where f(k)=k(k+3)/2 (A000096).

n	a(n)
1	5
2	59
3	599
4	5999
5	59999
6	599999
7	5999999
8	59999999
9	599999999
10	5999999999
11	59999999999
12	599999999999
13	5999999999999
14	59999999999999
15	599999999999999
16	5999999999999999
17	59999999999999999
18	599999999999999999
19	5999999999999999999
20	59999999999999999999
21	599999999999999999999

[5, 59, 599, 5999, 59999, 599999, 5999999, 59999999, 599999999, 5999999999, 59999999999, 599999999999, 5999999999999, 59999999999999, 599999999999999, 5999999999999999, 59999999999999999, 599999999999999999, 5999999999999999999, 59999999999999999999, 599999999999999999999]

cp's OEIS Frontend

A099151 Positive integers a such that f(3a)+f(a)=concatenation of 3a and a, where f(k)=k(k+3)/2 (A000096).

Table of values

List of values