A078251 - OEIS

%I #7 Mar 12 2015 23:54:07

%S 0,222,0,444444,55,666666,7777777777777777,888888888888888888,

%T 9999999999999999999999,1010101010101010101010101010,

%U 111111111111111111111111111111,121212,1313131313

%N a(n) = smallest multiple of the n-th prime whose decimal expansion is nnn...n, or 0 if no such number exists.

%C Conjecture: No entry is zero for n > 3.

%C No entry is zero for n > 3 because 10 is only divisible by the first and the third primes. In particular, for n>3 the number formed by nn..n (n-th prime - 1) n's is divisible by n-th prime. - _Sascha Kurz_, Jan 04 2003

%e a(6) = 666666 is the smallest multiple of 6th prime 13 using digit 6.

%K base,nonn

%O 1,2

%A _Amarnath Murthy_, Nov 24 2002

%E More terms from _Sascha Kurz_, Jan 04 2003