A048374 a(n)^3 is smallest cube containing exactly n 9's.

9, 31, 99, 998, 999, 7937, 9999, 99998, 99999, 996999, 999999, 6688699, 9999999, 97609999, 99969999, 999999998, 999899999, 9998999999, 9999999999, 9999699999, 99999989999, 99998999999, 997999998999

Offset: 1

Author

Patrick De Geest, Mar 15 1999

Keywords

• nonn
• base
• more

Comments

a(24) > 5*10^12, a(25) = 999996999999. - Giovanni Resta, Jun 29 2018

Links

• Eric Weisstein's World of Mathematics, Cubic Number

Crossrefs

Cf. A036536, A048365, A048366, A048367, A048368, A048369, A048370, A048371, A048372, A048373.

Programs

Mathematica

(* A048374 *)
nsmall = Table[Infinity, 11];
For[i = 0, i <= 10^6, i++, n0 = Count[IntegerDigits[i^3], 9];
  If[nsmall[[n0]] > i, nsmall[[ n0]] = i]];
nsmall(* Robert Price, Sep 26 2018 *)

Extensions

a(16)-a(22) from Lars Blomberg, Jun 12 2011

a(23) from Giovanni Resta, Jun 29 2018