OFFSET

1,1

COMMENTS

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.

EXAMPLE

38 is in the sequence because 38 == 2 (mod 3) and all even numbers congruent 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.

MATHEMATICA

ocn=Select[Range[3, 37, 2], !PrimeQ[#]&]; s=Total/@Tuples[ocn, 2]; Complement[Range[2, 38, 2], s] (* James C. McMahon, Sep 23 2024 *)

CROSSREFS

KEYWORD

fini,full,nonn

AUTHOR

Graeme McRae, Apr 11 2006

STATUS

approved