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A001800 as a simple table

na(n)
01
13
230
370
4315
5693
612012
725740
8109395
9230945
101939938
114056234
1216900975
1335102025
141163381400
152404321560
169917826435
1720419054425
18167890003050
19344616322050
201412926920405
212893136075115
2247342226683700
2396742811049300
24395033145117975

[1,3,30,70,315,693,12012,25740,109395,230945,
 1939938,4056234,16900975,35102025,1163381400,
 2404321560,9917826435,20419054425,167890003050,
 344616322050,1412926920405,2893136075115,
 47342226683700,96742811049300,395033145117975]