The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 1 | 3 |
| 2 | 7 |
| 3 | 13 |
| 4 | 31 |
| 5 | 69 |
| 6 | 190 |
| 7 | 444 |
| 8 | 1052 |
| 9 | 2702 |
| 10 | 6455 |
| 11 | 15928 |
| 12 | 40073 |
| 13 | 100370 |
| 14 | 251707 |
| 15 | 637321 |
| 16 | 1617175 |
| 17 | 4124448 |
| 18 | 10553415 |
| 19 | 27066978 |
| 20 | 69709680 |
| 21 | 179992909 |
| 22 | 465769803 |
| 23 | 1208198532 |
| 24 | 3140421716 |
| 25 | 8179002120 |
| 26 | 21338685408 |
| 27 | 55762149030 |
| 28 | 145935689361 |
| 29 | 382465573486 |
| 30 | 1003652347100 |
[3,7,13,31,69,190,444,1052,2702,6455,15928,40073, 100370,251707,637321,1617175,4124448,10553415, 27066978,69709680,179992909,465769803,1208198532, 3140421716,8179002120,21338685408,55762149030, 145935689361,382465573486,1003652347100] |