A189036 - OEIS

%I #7 Mar 31 2012 10:28:21

%S 0,2,3,1,5,30,7,6,6,70,11,12,13,126,120,2,17,42,19,30,210,286,23,66,

%T 10,390,1,56,29,930,31,10,462,646,420,15,37,798,624,170,41,1722,43,

%U 132,195,1150,47,21,14,90,1020,182,53,6,880,322,1254,1798,59,345,61,2046,357,3,1170,4026,67,306,1794,4130,71,78,73,2886,165,380,1386,5538,79,55,12,3526,83,651,1870,3870,2784,770,89,1230,1820,552,3162,4606,2280,102,97,154,825,35

%N a(n)= lcm(n,n')/gcd(n,n'), where n' is the arithmetic derivative of n.

%C Least common multiple of n and its arithmetic derivative divided by greatest common divisor of n and its arithmetic derivative.

%F a(n) = lcm(n,n')/gcd(n,n') = A086130(n)/A085731(n).

%e n = 8, n'= 12,  lcm(8,12)= 24, gcd(8,12)= 4, hence a(8)=24/4 = 6.

%Y Cf. A003415, A085731, A086130, A083345, A083346.

%K nonn

%O 1,2

%A _Giorgio Balzarotti_, Apr 15 2011