A078246 Smallest multiple of n using only digits 0 and 7.

7, 70, 777, 700, 70, 7770, 7, 7000, 777777777, 70, 77, 77700, 7007, 70, 7770, 70000, 77707, 7777777770, 77007, 700, 777, 770, 770707, 777000, 700, 70070, 7707777777, 700, 7707707, 7770, 777077, 700000, 777777, 777070, 70, 77777777700, 777, 770070

Offset: 1

Author

Amarnath Murthy, Nov 23 2002

Keywords

• base
• nonn

Comments

a(n) = min{A204094(k): k > 0 and A204094(k) mod n = 0}. [Reinhard Zumkeller, Jan 10 2012]

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..998

Crossrefs

Cf. A004290, A078241-A078248, A079339, A096681-A096688.

Programs

Haskell

a078246 n = head [x | x <- tail a204094_list, mod x n == 0]
-- Reinhard Zumkeller, Jan 10 2012

Mathematica

With[{c=Rest[FromDigits/@Tuples[{0,7},11]]},Table[SelectFirst[c, Divisible[ #,n]&],{n,40}]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Dec 27 2019 *)

Extensions

More terms from Ray Chandler, Jul 12 2004