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A220588 as a simple table

na(n)
01
10
2-2
3-4
4-4
52
622
772
8184
9422
10914
111916
123940
138010
1416174
1532528
1665264
17130766
18261802
19523908
201048156
212096690
224193798
238388056
2416776616
2533553782
2667108162
27134216972
28268434644
29536870042
301073740894
312147482656
324294966240
338589933470
3417179867994

[1,0,-2,-4,-4,2,22,72,184,422,914,1916,3940,8010,
 16174,32528,65264,130766,261802,523908,1048156,
 2096690,4193798,8388056,16776616,33553782,
 67108162,134216972,268434644,536870042,1073740894,
 2147482656,4294966240,8589933470,17179867994]