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Search: id:A118081
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| A118081 |
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Even numbers that can't be represented as the sum of two odd composite numbers. |
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+0
5
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| 2, 4, 6, 8, 10, 12, 14, 16, 20, 22, 26, 28, 32, 38
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Suggested by the familiar puzzle, "What is the largest even number that is not the sum of two odd composite numbers?" The sequence contains all even numbers that are not of the form (9+6k)+9, (9+6k)+25, or (9+6k)+35, where k is a nonnegative integer.
If 1 is allowed as a composite number, then only the eight numbers in A046458 are not representable. - T. D. Noe (noe(AT)sspectra.com), Jun 01 2008
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EXAMPLE
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38 is in the sequence because 38===2(mod 3), and all even numbers equivalent to 2 (mod 3) larger than 38 can be expressed as the sum of odd composites (9+6k) and 35, where k is a nonnegative integer.
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CROSSREFS
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Adjacent sequences: A118078 A118079 A118080 this_sequence A118082 A118083 A118084
Sequence in context: A100800 A094041 A058066 this_sequence A082893 A024807 A063459
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KEYWORD
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fini,nonn
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AUTHOR
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Graeme McRae (g_m(AT)mcraefamily.com), Apr 11 2006
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