a(n) = 5*binomial(n, 6).

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =5a(7) =35a(8) =140a(9) =420a(10) =1050a(11) =2310a(12) =4620a(13) =8580a(14) =15015a(15) =25025a(16) =40040a(17) =61880a(18) =92820a(19) =135660a(20) =193800a(21) =271320a(22) =373065a(23) =504735a(24) =672980a(25) =885500a(26) =1151150a(27) =1480050a(28) =1883700a(29) =2375100