A158912 - OEIS

%I #5 Oct 04 2012 16:26:59

%S 20,1218,7540,20280,1373090,4903600,23308460,316540365,527813814,

%T 4091661910,16718044954,1034412600,142903074740,1827252574658,

%U 31036383127940

%N Primitive numbers n whose square can be represented as a four "digit" repdigit number in some base < n.

%e 20^2 = 1111 in base 7

%e 1218^2 = (21)(21)(21)(21) in base 41

%e 7540^2 = (58)(58)(58)(58) in base 99

%Y A158235, A158245

%K nonn,base

%O 1,1

%A _T. D. Noe_, Mar 30 2009