A076254 - OEIS

A076254

A list of six integers with property that for every 3 numbers a,b,c from the list axbxc is an integer, where axb=a*b/(a+b) and axbxc=a*b*c/(a*b+a*c+b*c). This is the so-called replus operation.

%I #4 Mar 31 2012 14:39:57

%S 248971642920,497943285840,746914928760,995886571680,1493829857520,

%T 1991773143360

%N A list of six integers with property that for every 3 numbers a,b,c from the list axbxc is an integer, where axb=a*b/(a+b) and axbxc=a*b*c/(a*b+a*c+b*c). This is the so-called replus operation.

%C a(1) is the least common multiple of every ab+ac+bc, where a,b,c=1,2,3,4,6,8.

%D Zoltan Kovacs, Abacus 2001.5 (Hungarian periodical)

%F a(n)=n*a(1) for n=1, 2, 3, 4 a(5)=6*a(1), a(6)=8*a(1)

%e a(1)*a(2)*a(3) = a(1)*2a(1)*3a(1)/(a(1)*2a(1) + a(1)*3a(1) + 2a(1)*3a(1)) = 6a(1)/11 is an integer because 11 | a(1).

%K fini,full,nonn

%O 1,1

%A _Miklos Kristof_, Nov 05 2002