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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 5 |
| 2 | 15 |
| 3 | 35 |
| 4 | 71 |
| 5 | 135 |
| 6 | 255 |
| 7 | 495 |
| 8 | 992 |
| 9 | 2028 |
| 10 | 4186 |
| 11 | 8710 |
| 12 | 18335 |
| 13 | 39151 |
| 14 | 84711 |
| 15 | 185079 |
| 16 | 406994 |
| 17 | 899374 |
| 18 | 1996676 |
| 19 | 4453904 |
| 20 | 9980570 |
| 21 | 22454570 |
| 22 | 50688170 |
| 23 | 114750090 |
| 24 | 260454417 |
| 25 | 592628949 |
| 26 | 1351606335 |
| 27 | 3089310115 |
| 28 | 7075157399 |
| 29 | 16233066135 |
| 30 | 37307526647 |
[1,5,15,35,71,135,255,495,992,2028,4186,8710, 18335,39151,84711,185079,406994,899374,1996676, 4453904,9980570,22454570,50688170,114750090, 260454417,592628949,1351606335,3089310115, 7075157399,16233066135,37307526647] |