a(n) = concatenation of periods of periodic sequences of ending digits of multiples of n.

Terms

a(0) =1234567890a(1) =24680a(2) =3692581470a(3) =48260a(4) =50a(5) =62840a(6) =7418529630a(7) =86420a(8) =9876543210a(9) =0a(10) =1234567890a(11) =24680a(12) =3692581470a(13) =48260a(14) =50a(15) =62840a(16) =7418529630a(17) =86420a(18) =9876543210a(19) =0a(20) =1234567890a(21) =24680a(22) =3692581470a(23) =48260a(24) =50a(25) =62840a(26) =7418529630a(27) =86420a(28) =9876543210a(29) =0