a(n) = 1^n + 2^n + ... + 7^n.

Terms

a(0) =7a(1) =28a(2) =140a(3) =784a(4) =4676a(5) =29008a(6) =184820a(7) =1200304a(8) =7907396a(9) =52666768a(10) =353815700a(11) =2393325424a(12) =16279522916a(13) =111239118928a(14) =762963987380