The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 1 |
| 2 | 7 |
| 3 | 28 |
| 4 | 98 |
| 5 | 351 |
| 6 | 1261 |
| 7 | 4523 |
| 8 | 16233 |
| 9 | 58268 |
| 10 | 209132 |
| 11 | 750597 |
| 12 | 2693993 |
| 13 | 9669101 |
| 14 | 34703683 |
| 15 | 124556124 |
| 16 | 447048462 |
| 17 | 1604516243 |
| 18 | 5758821685 |
| 19 | 20669175143 |
| 20 | 74184412085 |
| 21 | 266257698140 |
| 22 | 955634207080 |
| 23 | 3429897967721 |
| 24 | 12310358902801 |
[1,7,28,98,351,1261,4523,16233,58268,209132, 750597,2693993,9669101,34703683,124556124, 447048462,1604516243,5758821685,20669175143, 74184412085,266257698140,955634207080, 3429897967721,12310358902801] |