A109940 Largest k-digit multiple of n where k is the number of digits in n.

9, 8, 9, 8, 5, 6, 7, 8, 9, 90, 99, 96, 91, 98, 90, 96, 85, 90, 95, 80, 84, 88, 92, 96, 75, 78, 81, 84, 87, 90, 93, 96, 99, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67

Offset: 1

Author

Amarnath Murthy, Jul 19 2005

Keywords

• base
• easy
• nonn

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A097326.

Programs

Mathematica

Table[Quotient[10^IntegerLength[n]-1,n]n,{n,60}] (* Harvey P. Dale, Oct 16 2011 *)

PARI

a(n) = n * ((10^#digits(n)-1)\n) \\ Rémy Sigrist, Nov 01 2024

Formula

a(n) = n * A097326(n). - Rémy Sigrist, Nov 01 2024