n*(n^10+1)/2.

Terms

a(0) =0a(1) =1a(2) =1025a(3) =88575a(4) =2097154a(5) =24414065a(6) =181398531a(7) =988663375a(8) =4294967300a(9) =15690529809a(10) =50000000005a(11) =142655835311a(12) =371504185350a(13) =896080197025