A143473 Replace the leading digit d of n with 10-d (in decimal representation).

10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 30, 31

Offset: 0

Author

Reinhard Zumkeller, Aug 18 2008

Keywords

• nonn
• base
• look

Comments

a(n) = n iff A000030(n) = 5, cf. A217398.

Links

• R. Zumkeller, Table of n, a(n) for n = 0..9999

Programs

Haskell

a143473 n = foldl (\v d -> 10 * v + d) 0 $ (10 - z) : zs where
   (z:zs) = map (read . return) $ show n

Mathematica

ld10[n_]:=Module[{idn=IntegerDigits[n]},FromDigits[Join[{10-idn[[1]]},Rest[ idn]]]]; Array[ld10,100,0] (* Harvey P. Dale, May 25 2020 *)

Formula

A000030(a(n)) = 10 - A000030(n).