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

A319874

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

Terms

    a(0) =10a(1) =90a(2) =720a(3) =5040a(4) =30240a(5) =151200a(6) =604800a(7) =1814400a(8) =3628800a(9) =3628800a(10) =3628820a(11) =3629180a(12) =3635640a(13) =3745080a(14) =5489280a(15) =31536000a(16) =394329600a(17) =5082739200a(18) =60952953600a(19) =670446201600a(20) =670446201630a(21) =670446202470a(22) =670446225960a(23) =670446859320a(24) =670463302320a(25) =670873719600

External references