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Let S = 123456789101112131415..., the concatenation of the natural numbers; partition this string into distinct squarefree numbers. To avoid leading zeros, no number may end at the digit that comes before a 0 in S.
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%I #6 Dec 05 2013 19:56:19

%S 1,2,3,4567,89,10,11,1213,14,15,161,7,181,9202,122,23,242526,27282,

%T 930,31,323,33,43,5,3637,38,39,404142,434,445,46,47,4849,505,15253,

%U 545,55,6,57,58,59,606,1626,3646,566,67,6869,70,71,727,37,4757,677,78,79,8081,82

%N Let S = 123456789101112131415..., the concatenation of the natural numbers; partition this string into distinct squarefree numbers. To avoid leading zeros, no number may end at the digit that comes before a 0 in S.

%e a(18) = 27282 because 27282 is squarefree, while 27, 272 and 2728 are not and 2 has already been used.

%e a(19) = 930 because 9 is not squarefree and 93 would cause a(20) to have a leading 0.

%K base,easy,nonn

%O 0,2

%A _Amarnath Murthy_, Jul 14 2003

%E More terms from _David Wasserman_, Feb 14 2005