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A043631
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Numbers whose base-9 representation has exactly 2 runs.
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1
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9, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 24, 25, 26, 27, 28, 29, 31, 32, 33, 34, 35, 36, 37, 38, 39, 41, 42, 43, 44, 45, 46, 47, 48, 49, 51, 52, 53, 54, 55, 56, 57, 58, 59, 61, 62, 63, 64, 65, 66, 67, 68, 69, 71, 72, 73, 74, 75, 76, 77, 78, 79, 81, 90, 92, 93, 94, 95
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OFFSET
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1,1
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LINKS
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MAPLE
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rlen := proc(n, ba) local rs, s, dgs, i ; rs :=0 ; s := 0; dgs := convert(n, base, ba) ; for i from 1 to nops(dgs) do if s = 0 then s :=1 ; else if op(i, dgs) <> op(i-1, dgs) then rs := rs+1 ; s :=1 ; else s :=s+1 ; fi; fi; od: rs := rs+1 ; RETURN (rs) ; end: for n from 1 to 200 do if rlen(n, 9) = 2 then printf("%d, ", n) ; fi; od: # R. J. Mathar, Oct 20 2008
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MATHEMATICA
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Select[Range[100], Length[Split[IntegerDigits[#, 9]]]==2&] (* Harvey P. Dale, Jan 06 2022 *)
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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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EXTENSIONS
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STATUS
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approved
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