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A154387
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Composite numbers with even sum of digits.
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1
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4, 6, 8, 15, 20, 22, 24, 26, 28, 33, 35, 39, 40, 42, 44, 46, 48, 51, 55, 57, 60, 62, 64, 66, 68, 75, 77, 80, 82, 84, 86, 88, 91, 93, 95, 99, 105, 110, 112, 114, 116, 118, 121, 123, 125, 129, 130, 132, 134, 136, 138, 141, 143, 145, 147, 150, 152, 154, 156, 158, 161
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OFFSET
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1,1
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LINKS
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EXAMPLE
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15 is composite and 1 + 5 = 6 (an even number), so 15 is a term;
20 is composite and 2 + 0 = 2 (an even number), so 20 is a term.
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MAPLE
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sd := proc (n) options operator, arrow: add(convert(n, base, 10)[j], j = 1 .. nops(convert(n, base, 10))) end proc: a := proc (n) if isprime(n) = false and `mod`(sd(n), 2) = 0 then n else end if end proc: seq(a(n), n = 2 .. 180); # Emeric Deutsch, Jan 17 2009
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MATHEMATICA
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Select[Range[200], CompositeQ[#]&&EvenQ[Total[IntegerDigits[#]]]&] (* Harvey P. Dale, Aug 25 2016 *)
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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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