login

A015640 as a simple table

na(n)
10
20
30
40
51
66
721
856
9126
10251
11461
12786
131281
141981
152981
164311
176131
188436
1911496
2015246
2120076
2225851
2333166
2441656
2552281
2664436
2779316
2896151
29116626
30139246
31166651
32196751
33232501
34271601
35317961
36367616
37426521
38489506

[0,0,0,0,1,6,21,56,126,251,461,786,1281,1981,2981,
 4311,6131,8436,11496,15246,20076,25851,33166,
 41656,52281,64436,79316,96151,116626,139246,
 166651,196751,232501,271601,317961,367616,426521,
 489506]