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A371050
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Numbers whose ternary representation consists of a run of 1's, then a run of 2's, then a run of 0's.
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1
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15, 42, 45, 51, 123, 126, 132, 135, 153, 159, 366, 369, 375, 378, 396, 402, 405, 459, 477, 483, 1095, 1098, 1104, 1107, 1125, 1131, 1134, 1188, 1206, 1212, 1215, 1377, 1431, 1449, 1455, 3282, 3285, 3291, 3294, 3312, 3318, 3321, 3375, 3393, 3399, 3402, 3564
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OFFSET
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1,1
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COMMENTS
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All the numbers are multiples of 3.
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LINKS
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EXAMPLE
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The ternary representations of 15, 42, 45 are 120, 1120, 1200.
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MATHEMATICA
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Map[#[[1]] &, Select[Map[{#, Map[#[[1]] &, Split[IntegerDigits[#, 3]]] == {1, 2, 0}} &,
Range[0, 4000, 3]], #[[2]] &]] (* this sequence *)
Map[IntegerString[#, 3] &, %] (* A371051 *)
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PROG
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(Python)
from itertools import count, islice
def A371050_gen(): # generator of terms
return ((3**b*(3**(l-a)-1>>1)+3**b-1)*3**(a-b) for l in count(3) for a in range(2, l) for b in range(1, a))
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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