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A110978 Odd integers that are nonprime, such that there exist two factors of each number that when multiplied together in binary base, do not ever require the use of a "carry" bit. 0

%I #2 Dec 09 2007 03:00:00

%S 15,27,45,51,63,85,95,99,111,119,123,125,153,165,175,187,189,195,207,

%T 219,221,231,243,245,255,297,315,325,335,363,365,387,399,411,429,435,

%U 441,447,455,483,485,495,507,511,561,585,603,621,627,629,639,645,655

%N Odd integers that are nonprime, such that there exist two factors of each number that when multiplied together in binary base, do not ever require the use of a "carry" bit.

%e 45 = 5*9:

%e ....1001.(9)

%e ...*.101.(times.5)

%e .-------

%e ....1001

%e ...00000

%e ..100100

%e .-------

%e ..101101.(=45)

%e No carry bit needed!

%K base,easy,nonn

%O 0,1

%A Paul Klemstine (paulklemstine(AT)yahoo.com), Sep 29 2005

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Last modified March 29 08:13 EDT 2024. Contains 371265 sequences. (Running on oeis4.)