# A301335 (b-file synthesized from sequence entry)
0 1
1 1
2 4
3 27
4 260
5 3175
6 47304
7 833147
8 16941120
9 390611331
10 10070060200
11 287028156162
12 8962583345856
13 304255011200647
14 11156593415089808
15 439452231820920000
16 18505340390664634384
17 829599437871129843839
18 39447684087807950938908
19 1983038000428208822539998
20 105080571577382659860160800