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A103756
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Number of contiguous digits i in the counting numbers, for i=2.
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1
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1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 2, 2, 5, 2, 2, 2, 2, 2, 2, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1
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OFFSET
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1,5
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COMMENTS
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Write the natural numbers as an infinite sequence of digits, starting at the left; and count the digits of each group of "2"'s you encounter (the smallest "groups" have one "2").
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LINKS
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EXAMPLE
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a(1)=1: the first "2" of the counting numbers, isolated.
a(2)=1: the second "2", second digit of number 12, isolated.
a(3)=1 the first digit of number 20, isolated.
a(4)=1: the first digit of number 21, isolated.
a(5)=3: two "2"'s of 22 followed by one "2" of 23 = three "2"'s, the next group of "2"'s.
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MATHEMATICA
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Length/@Select[Split[Flatten[IntegerDigits/@Range[300]]], Union[#]=={2}&] (* Harvey P. Dale, Jun 10 2023 *)
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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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