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A118081 Even numbers that can't be represented as the sum of two odd composite numbers. +0
5
2, 4, 6, 8, 10, 12, 14, 16, 20, 22, 26, 28, 32, 38 (list; graph; listen)
OFFSET

1,1

COMMENT

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

EXAMPLE

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.

CROSSREFS

Sequence in context: A100800 A094041 A058066 this_sequence A152483 A162764 A082893

Adjacent sequences: A118078 A118079 A118080 this_sequence A118082 A118083 A118084

KEYWORD

fini,nonn

AUTHOR

Graeme McRae (g_m(AT)mcraefamily.com), Apr 11 2006

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Last modified November 25 20:09 EST 2009. Contains 167514 sequences.


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