a(n) = (1/2)*(n + 1)*(5*n^2 + 15*n + 6)*Pochhammer(n, 6) / 6!.

Terms

a(0) =0a(1) =26a(2) =588a(3) =5376a(4) =30660a(5) =129780a(6) =446292a(7) =1315776a(8) =3444012a(9) =8198190a(10) =18058040a(11) =37285248a(12) =72882264a(13) =135925608a(14) =243374040a(15) =420468480a(16) =703858344a(17) =1145608002a(18) =1818257364a(19) =2821132160a(20) =4288122300a(21) =6397170780a(22) =9381740940a(23) =13544556480a(24) =19273936500a(25) =27063076950a(26) =37532660256