a(n) = 9*8*7*6*5*4*3*2*1 - 18*17*16*15*14*13*12*11*10 + 27*26*25*24*23*22*21*20*19 - ... + (up to the n-th term).

A319892

a(n) = 9*8*7*6*5*4*3*2*1 - 18*17*16*15*14*13*12*11*10 + 27*26*25*24*23*22*21*20*19 - ... + (up to the n-th term).

Terms

    a(0) =9a(1) =72a(2) =504a(3) =3024a(4) =15120a(5) =60480a(6) =181440a(7) =362880a(8) =362880a(9) =362862a(10) =362574a(11) =357984a(12) =289440a(13) =-665280a(14) =-13003200a(15) =-160030080a(16) =-1763959680a(17) =-17642862720a(18) =-17642862693a(19) =-17642862018a(20) =-17642845170a(21) =-17642441520a(22) =-17633175120a(23) =-17429735520a(24) =-13167191520a(25) =71870561280

External references