A100658 - OEIS

%I #3 Oct 01 2013 17:58:05

%S 6,10,12,14,15,18,20,21,24,26,28,30,33,34,35,36,38,39,40,42,45,46,48,

%T 50,51,52,54,55,56,57,60,62,63,65,66,68,69,70,72,74,75,76,77,78,80,82,

%U 84,85,86,87,90,91,92,93,95,96,98,99,100,102,104,105,106,108,110,111,112

%N Composite numbers with at least 2 factors that have different digital roots.

%o (PARI) nsamedr(n) = { local(j); for(j=2,n, if(!isprime(j)&!issamedr(j),print1(j",")) ) } issamedr(n) = { local(f,a,ln,x); f=0; a=ifactor(n); ln=length(a); for(x=1,ln-1, if(droot(a[x])<>droot(a[x+1]), f=1;break)); if(f==0&ln>1,return(1),return(0)) } droot(n) = \ the digital root of a number. { local(x); x= n%9; if(x>0,return(x),return(9)) }

%K base,easy,nonn

%O 1,1

%A _Cino Hilliard_, Jan 02 2005