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A137667 The sequence alternates even and odd integers but also even and odd digits; it is monotonically increasing and a(n) is always the smallest integer fitting the pattern. 0

%I #4 May 30 2013 13:15:44

%S 0,1,2,3,4,5,6,7,8,9,210,301,410,501,610,701,810,901,21010,30101,

%T 41010,50101,61010,70101,81010,90101,2101010,3010101,4101010,5010101,

%U 6101010,7010101,8101010,9010101,210101010,301010101,410101010,501010101

%N The sequence alternates even and odd integers but also even and odd digits; it is monotonically increasing and a(n) is always the smallest integer fitting the pattern.

%e The integer after "9" must be even, must start with an even digit and must be the smallest one larger than "9"; only "210" satisfies all requirements. The integer after "210" must be odd, must start with an odd digit and must be the smallest one larger than "210"; only "301" fits, etc.

%K base,easy,nonn

%O 0,3

%A _Eric Angelini_, Apr 27 2008

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Last modified April 19 08:20 EDT 2024. Contains 371782 sequences. (Running on oeis4.)