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A001873 as a simple table

na(n)
01
15
220
365
4190
5511
61295
73130
87285
916435
1036122
1177645
12163730
13339535
14693835
151399478
162790100
175504650
1810758050
1920845300
2040075630
2176495450
22145052300
23273381350
24512347975
25955187033
261772132390
273272875935
286018885570
2911024814945
3020118711993

[1,5,20,65,190,511,1295,3130,7285,16435,36122,
 77645,163730,339535,693835,1399478,2790100,
 5504650,10758050,20845300,40075630,76495450,
 145052300,273381350,512347975,955187033,
 1772132390,3272875935,6018885570,11024814945,
 20118711993]