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A248821 as a simple table

na(n)
11
21
31
42
56
610
736
864
9220
10468
111024
122052
137590
1416224
1550400
16142800
17246240
18510300
192261952
203545856
2114152320
2240986000
2368428800
24178293960
25784274400
261526805504
272782080000
289307872000
2915858633600
3028225260000
31143730892800
32225167040000

[1,1,1,2,6,10,36,64,220,468,1024,2052,7590,16224,
 50400,142800,246240,510300,2261952,3545856,
 14152320,40986000,68428800,178293960,784274400,
 1526805504,2782080000,9307872000,15858633600,
 28225260000,143730892800,225167040000]