A096683 Least k such that decimal representation of k*n contains only digits 0 and 4.

4, 2, 148, 1, 8, 74, 572, 5, 49382716, 4, 4, 37, 308, 286, 296, 25, 2612, 24691358, 2316, 2, 1924, 2, 19148, 185, 16, 154, 163127572, 143, 151876, 148, 14324, 125, 13468, 1306, 1144, 12345679, 12, 1158, 1036, 1, 1084, 962, 102428, 1, 98765432

Offset

1,1

Links

Robert G. Wilson v, Table of n, a(n) for n = 1..10000

Formula

a(n) = A078243(n)/n.

Mathematica

f[n_] := Block[{id = {0, 4}, k = 1}, While[ Union[ Join[id, IntegerDigits[k*n]]] != id, k++]; k]; Array[f, 100] (* or *)
id = {0, 7}; lst = Union[ FromDigits /@ Flatten[ Table[ Tuples[id, j], {j, 15}], 1]]; If[ lst[[1]] == 0, lst = Rest@ lst]; f[n_] := (Min[ Select[lst, Mod[#, n] == 0 &]]/n) /. Infinity -> 0; Array[f, 100] (* or *)
id = {0, 7}; lst = Union[ FromDigits /@ Flatten[ Table[ Tuples[id, j], {j, 15}], 1]]; If[ lst[[1]] == 0, lst = Rest@ lst]; f[n_] := (SelectFirst[lst, Mod[#, n] == 0 &, 0]/n); a = Array[f, 100] (* requires Mathematica v10 *) (* Robert G. Wilson v, Sep 26 2016 *)

Crossrefs

Cf. A004290, A078241-A078248, A079339, A096681, A096682, A096684, A096685, A096686, A096687, A096688.

Sequence in context: A266069 A057167 A355646 * A158903 A273148 A276342

Adjacent sequences: A096680 A096681 A096682 * A096684 A096685 A096686

Keyword

base,nonn

Author

Ray Chandler, Jul 12 2004

Status

approved