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A037308
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Numbers whose base-2 and base-10 expansions have the same digit sum.
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19
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0, 1, 20, 21, 122, 123, 202, 203, 222, 223, 230, 231, 302, 303, 410, 411, 502, 503, 1130, 1131, 1150, 1151, 1202, 1203, 1212, 1213, 1230, 1231, 1300, 1301, 1402, 1403, 1502, 1503, 1510, 1511, 2006, 2007, 2032, 2033, 2102, 2103, 2200, 2201, 3006, 3007, 3012
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OFFSET
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1,3
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COMMENTS
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n is in the sequence iff n+(-1)^n is in the sequence. [Robert Israel, Mar 25 2013]
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LINKS
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FORMULA
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EXAMPLE
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122 is a member, since digital-sum_2(122) = 5 = digital-sum_10(122).
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MAPLE
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N:= 10000; # to get all elements up to N
select(x -> (convert(convert(x, base, 10), `+`)-convert(convert(x, base, 2), `+`)=0), [$0..N]); # Robert Israel, Mar 25 2013
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MATHEMATICA
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Select[Range[0, 5000], Total[IntegerDigits[#, 2]] == Total[IntegerDigits[#, 10]] &] (* Jean-François Alcover, Mar 07 2016 *)
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PROG
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(Sage) [n for n in (0..10000) if sum(n.digits(base=2)) == sum(n.digits(base=10))] # Freddy Barrera, Oct 12 2018
(Python)
def ok(n): return sum(map(int, str(n))) == sum(map(int, bin(n)[2:]))
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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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