The OEIS is supported by the many generous donors to the OEIS Foundation.
A271603 as a simple table
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 4 |
| 2 | 28 |
| 3 | 136 |
| 4 | 604 |
| 5 | 2596 |
| 6 | 10308 |
| 7 | 41756 |
| 8 | 167884 |
| 9 | 666916 |
| 10 | 2644596 |
| 11 | 10503884 |
| 12 | 41783516 |
| 13 | 166468132 |
| 14 | 664068284 |
| 15 | 2651397964 |
[1,4,28,136,604,2596,10308,41756,167884,666916, 2644596,10503884,41783516,166468132,664068284, 2651397964] |