The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 13 |
| 2 | 345 |
| 3 | 673 |
| 4 | 7257 |
| 5 | 28428 |
| 6 | 184145 |
| 7 | 866944 |
| 8 | 4737473 |
| 9 | 23297196 |
| 10 | 120376601 |
| 11 | 598856998 |
| 12 | 3032621917 |
| 13 | 15138719850 |
| 14 | 76078222215 |
| 15 | 380193902100 |
| 16 | 1904900579053 |
| 17 | 9522965707286 |
| 18 | 47655682592913 |
| 19 | 238267659404765 |
| 20 | 1191769118082757 |
[13,345,673,7257,28428,184145,866944,4737473, 23297196,120376601,598856998,3032621917, 15138719850,76078222215,380193902100, 1904900579053,9522965707286,47655682592913, 238267659404765,1191769118082757] |