A147551 - OEIS

%I #10 May 01 2013 21:11:53

%S 1,4,32,240,2304,20736,184320,1843200,17740800,170311680,1642291200,

%T 16057958400,153280512000,1532805120000,15229951672320,

%U 147149291520000,1456777986048000,14214621560832000,140724753452236800

%N Minimum of A000010(m) where m is an n-digit number.

%H H. v. Eitzen, <a href="/A147551/b147551.txt">Table of n, a(n) for n = 1..31</a>

%F a(n) = A000010(A147550(n))

%t a[n_]:=Min[EulerPhi[Range[10^(n-1),10^n-1]]];Do[Print[a[n]],{n,10}]

%o (PARI) a(n)=if(n<3,return(3*n-2));my(t=eulerphi(10^(n-1)));forstep(k=(10^n\300+1)*30,10^n,30,if(eulerphi(k)<t,t=eulerphi(k)));t \\ _Charles R Greathouse IV_, Feb 21 2013

%Y Cf. A147550.

%K base,nonn

%O 1,2

%A _Farideh Firoozbakht_, Nov 23 2008

%E More terms from _Hagen von Eitzen_, Jun 05 2009

%E Offsets in b-file corrected by _N. J. A. Sloane_, Aug 31 2009