The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 141 |
| 3 | 41414 |
| 4 | 1414141 |
| 5 | 314141413 |
| 6 | 33141414133 |
| 7 | 3331414141333 |
| 8 | 14333141414133341 |
| 9 | 121433314141413334121 |
| 10 | 1012143331414141333412101 |
| 11 | 17101214333141414133341210171 |
| 12 | 3171012143331414141333412101713 |
| 13 | 19317101214333141414133341210171391 |
[4,141,41414,1414141,314141413,33141414133, 3331414141333,14333141414133341, 121433314141413334121,1012143331414141333412101, 17101214333141414133341210171, 3171012143331414141333412101713, 19317101214333141414133341210171391] |