The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 10 |
| 3 | 22 |
| 4 | 45 |
| 5 | 90 |
| 6 | 177 |
| 7 | 344 |
| 8 | 666 |
| 9 | 1286 |
| 10 | 2482 |
| 11 | 4788 |
| 12 | 9232 |
| 13 | 17798 |
| 14 | 34309 |
| 15 | 66136 |
| 16 | 127485 |
| 17 | 245738 |
| 18 | 473678 |
| 19 | 913046 |
| 20 | 1759956 |
| 21 | 3392428 |
| 22 | 6539118 |
| 23 | 12604558 |
| 24 | 24296069 |
| 25 | 46832182 |
| 26 | 90271937 |
| 27 | 174004756 |
| 28 | 335404954 |
| 29 | 646513838 |
| 30 | 1246195494 |
| 31 | 2402119052 |
| 32 | 4630233348 |
| 33 | 8925061742 |
[1,4,10,22,45,90,177,344,666,1286,2482,4788,9232, 17798,34309,66136,127485,245738,473678,913046, 1759956,3392428,6539118,12604558,24296069, 46832182,90271937,174004756,335404954,646513838, 1246195494,2402119052,4630233348,8925061742] |