A204094 - OEIS

A204094

Numbers whose set of base 10 digits is {0,7}.

0, 7, 70, 77, 700, 707, 770, 777, 7000, 7007, 7070, 7077, 7700, 7707, 7770, 7777, 70000, 70007, 70070, 70077, 70700, 70707, 70770, 70777, 77000, 77007, 77070, 77077, 77700, 77707, 77770, 77777, 700000, 700007, 700070, 700077, 700700, 700707, 700770, 700777

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,2

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 0..10000

FORMULA

a(n) = 7 * A007088(n).

MATHEMATICA

FromDigits/@Tuples[{0, 7}, 6] (* Harvey P. Dale, Mar 03 2021 *)

PROG

(Haskell)

a204094 n = a204094_list !! n