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a(1) = 1, a(n) = smallest palindromic nontrivial multiple of a(n-1) containing all decimal digits of a(n-1).
1

%I #20 Mar 08 2021 22:49:30

%S 1,11,121,12221,2102012,21022222012,2102243223422012,

%T 2102245325665235422012,210224532568625787526865235422012

%N a(1) = 1, a(n) = smallest palindromic nontrivial multiple of a(n-1) containing all decimal digits of a(n-1).

%C Differs from A082776 at a(5). a(n) <= (10^A055642(a(n-1))+1)*a(n-1). If a(n-1) > 10 and the last digit of a(n-1) <= 4, then a(n) <= (10^(A055642(a(n-1))-1)+1)*a(n-1).

%e a(3) = 121 is a palindromic multiple of a(2) = 11 and contains two '1', all the digits of a(2).

%Y Cf. A055642, A082776.

%K nonn,base,more

%O 1,2

%A _Chai Wah Wu_, Mar 06 2021

%E a(9) from _Martin Ehrenstein_, Mar 07 2021

%E a(9) corrected by _Chai Wah Wu_, Mar 08 2021