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a(1) = 1, a(n) = smallest square obtained by prefixing a multiple of n to a(n-1).
2

%I #5 Dec 05 2013 19:56:32

%S 1,81,19881,1926419881,121775642151926419881,

%T 235039690681119003888121775642151926419881,

%U 36607881966437971419803962177283371311043235039690681119003888121775642151926419881

%N a(1) = 1, a(n) = smallest square obtained by prefixing a multiple of n to a(n-1).

%e a(2) = 81, a(3) = 19881 = 141^2 is obtained by prefixing 198 =3*66, to 81.

%Y Cf. A088064.

%K base,nonn

%O 1,2

%A _Amarnath Murthy_, Sep 21 2003

%E Corrected and extended by _Hans Havermann_, Mar 01 2004