The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 18 |
| 3 | 100 |
| 4 | 294 |
| 5 | 1210 |
| 6 | 2028 |
| 7 | 4624 |
| 8 | 6498 |
| 9 | 11638 |
| 10 | 23548 |
| 11 | 28830 |
| 12 | 49284 |
| 13 | 67240 |
| 14 | 77658 |
| 15 | 101614 |
| 16 | 146068 |
| 17 | 201898 |
| 18 | 223260 |
| 19 | 296274 |
| 20 | 352870 |
| 21 | 383688 |
| 22 | 486798 |
| 23 | 564898 |
| 24 | 697048 |
| 25 | 903264 |
| 26 | 1020100 |
| 27 | 1082118 |
| 28 | 1213594 |
| 29 | 1283148 |
| 30 | 1430128 |
| 31 | 2032254 |
| 32 | 2230930 |
[4,18,100,294,1210,2028,4624,6498,11638,23548, 28830,49284,67240,77658,101614,146068,201898, 223260,296274,352870,383688,486798,564898,697048, 903264,1020100,1082118,1213594,1283148,1430128, 2032254,2230930] |