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A371109
Ternary numbers that are concatenated runs C(1)B(1)A(1)C(2)B(2)A(2)...C(k)B(k)A(k), where A(i) is a run of 1's, B(i) a run of 0's, and C(i) a run of 2's, for i = 1..k.
7
201, 2001, 2011, 2201, 20001, 20011, 20111, 22001, 22011, 22201, 200001, 200011, 200111, 201111, 201201, 220001, 220011, 220111, 222001, 222011, 222201, 2000001, 2000011, 2000111, 2001111, 2001201, 2011111, 2011201, 2012001, 2012011, 2012201, 2200001
OFFSET
1,1
MATHEMATICA
Map[#[[1]] &, Select[Map[{#, DeleteDuplicates[Partition[Map[#[[1]] &, Split[IntegerDigits[#, 3]]], UpTo[3]]] == {{2, 0, 1}}} &,
Range[1, 3600, 3]], #[[2]] &]] (* this sequence *)
m = Map[{#, IntegerString[#, 3]} &, %];
Map[Last, ToExpression[m]] (* A371110 *)
(*Peter J. C. Moses, Mar 06 2024 *)
KEYWORD
nonn,base
AUTHOR
Clark Kimberling, Mar 31 2024
STATUS
approved