# A048421 (b-file synthesized from sequence entry) 1 3249 2 81225 3 225625 4 364816 5 2079364 6 4950625 7 39601849 8 44156025 9 84180625 10 92294449 11 116964225 12 267289801 13 341991049 14 643890625 15 1212780625 16 1445900625 17 1699500625 18 2307361225 19 2924105625 20 2998438564 21 3204126025