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A176100
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Even numbers that are not semiprimes, or, twice the nonprimes.
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4
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0, 2, 8, 12, 16, 18, 20, 24, 28, 30, 32, 36, 40, 42, 44, 48, 50, 52, 54, 56, 60, 64, 66, 68, 70, 72, 76, 78, 80, 84, 88, 90, 92, 96, 98, 100, 102, 104, 108, 110, 112, 114, 116, 120, 124, 126, 128, 130, 132, 136, 138, 140, 144, 148, 150, 152, 154, 156, 160, 162, 164
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refs;
listen;
history;
text;
internal format)
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OFFSET
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1,2
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LINKS
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Table of n, a(n) for n=1..61.
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FORMULA
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a(n)= 2*A141468(n).
A005843 \ A100484.
a(n) = A139270(n-1). [R. J. Mathar, May 03 2010]
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MATHEMATICA
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2 Prepend[Select[Range@ 82, ! PrimeQ@ # &], 0] (* Michael De Vlieger, Feb 20 2017 *)
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PROG
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(PARI) isok(n) = !(n%2) && !isprime(n/2); \\ Michel Marcus, Feb 20 2017
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CROSSREFS
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Cf. A001358, A005843, A100484, A141468.
Sequence in context: A340969 A180634 A139270 * A285658 A284802 A067884
Adjacent sequences: A176097 A176098 A176099 * A176101 A176102 A176103
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KEYWORD
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nonn,easy
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AUTHOR
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Juri-Stepan Gerasimov, Apr 08 2010, Apr 11 2010
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EXTENSIONS
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Entries checked by R. J. Mathar, Apr 16 2010
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STATUS
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approved
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