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| n | a(n) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 2 |
| 3 | 14 |
| 4 | 76 |
| 5 | 388 |
| 6 | 1950 |
| 7 | 9762 |
| 8 | 48824 |
| 9 | 244136 |
| 10 | 1220698 |
| 11 | 6103510 |
| 12 | 30517572 |
| 13 | 152587884 |
| 14 | 762939446 |
| 15 | 3814697258 |
| 16 | 19073486320 |
| 17 | 95367431632 |
| 18 | 476837158194 |
| 19 | 2384185791006 |
| 20 | 11920928955068 |
| 21 | 59604644775380 |
| 22 | 298023223876942 |
| 23 | 1490116119384754 |
| 24 | 7450580596923816 |
| 25 | 37252902984619128 |
[0,0,2,14,76,388,1950,9762,48824,244136,1220698, 6103510,30517572,152587884,762939446,3814697258, 19073486320,95367431632,476837158194, 2384185791006,11920928955068,59604644775380, 298023223876942,1490116119384754,7450580596923816, 37252902984619128] |