The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 54 |
| 3 | 1250 |
| 4 | 9604 |
| 5 | 146410 |
| 6 | 399854 |
| 7 | 2004504 |
| 8 | 3909630 |
| 9 | 12313004 |
| 10 | 49509670 |
| 11 | 73881680 |
| 12 | 213654354 |
| 13 | 395606540 |
| 14 | 526495354 |
| 15 | 897861304 |
| 16 | 1846372554 |
| 17 | 3514034690 |
| 18 | 4292210710 |
| 19 | 7536519254 |
| 20 | 10672906020 |
| 21 | 12608819004 |
| 22 | 20254042120 |
| 23 | 27241076254 |
[4,54,1250,9604,146410,399854,2004504,3909630, 12313004,49509670,73881680,213654354,395606540, 526495354,897861304,1846372554,3514034690, 4292210710,7536519254,10672906020,12608819004, 20254042120,27241076254] |