A131929 - OEIS

%I #11 Jan 10 2023 01:20:45

%S 0,1,1,0,1,0,1,0,0,0,1,1,1,0,1,0,1,0,1,1,0,1,1,1,1,1,0,1,1,1,1,1,1,0,

%T 1,1,1,0,1,0,1,1,1,0,1,0,1,0,0,1,0,1,1,0,1,0,0,0,1,0,1,1,1,0,1,0,1,0,

%U 0,1,1,1,1,0,1,0,1,0,1,0,0,1,1,0,1,0,0,0,1,0,0,1,1,0,1,0,1,0,0,0,1,1,1,0,1

%N Number of prime factors of n that are contained in decimal representation of n.

%C a(A050695(n)) = 0; a(A131930(n)) > 0;

%C a(A131931(n)) = n and a(m) <> n for m < A131931(n).

%H Reinhard Zumkeller, <a href="/A131929/b131929.txt">Table of n, a(n) for n = 1..10000</a>

%e a(230) = a(23*5*2) = #{2,23} = 2.

%Y Cf. A131930, A131931.

%K nonn,base

%O 1,132

%A _Reinhard Zumkeller_, Jul 30 2007