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Least common multiple of cototient values of consecutive integers.
2

%I #15 Feb 01 2015 16:40:37

%S 0,1,2,2,4,4,4,12,6,6,8,8,8,56,56,8,12,12,12,36,36,12,16,80,70,126,

%T 144,16,22,22,16,208,234,198,264,24,20,60,120,24,30,30,24,168,168,24,

%U 32,224,210,570,532,28,36,180,480,672,210,30,44,44,32,864,864,544,782,46,36

%N Least common multiple of cototient values of consecutive integers.

%H Charles R Greathouse IV, <a href="/A083548/b083548.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = lcm(A051953(n), A051953(n+1)).

%t f[x_] := x-EulerPhi[x] Table[LCM[f[w+1], f[w]], {w, 1, b}]

%t LCM@@#&/@Partition[Table[n-EulerPhi[n],{n,70}],2,1] (* _Harvey P. Dale_, Feb 01 2015 *)

%o (PARI) a(n)=lcm(n-eulerphi(n),n+1-eulerphi(n+1)) \\ _Charles R Greathouse IV_, Nov 16 2012

%Y Cf. A051953, A083538-A083555, A049586.

%K nonn

%O 1,3

%A _Labos Elemer_, May 22 2003