A048372 a(n)^3 is smallest cube containing exactly n 7's.

3, 26, 83, 173, 1983, 2953, 19753, 90643, 258999, 426859, 4255753, 13955253, 42111153, 92356426, 425851173, 878398753, 9197190176, 9196397753, 89494606688, 390974932563, 918856391641, 4250703842293

Offset: 1

Author

Patrick De Geest, Mar 15 1999

Keywords

• nonn
• base
• more

Links

• Eric Weisstein's World of Mathematics, Cubic Number

Crossrefs

Cf. A036534, A048365, A048366, A048367, A048368, A048369, A048370, A048371, A048373, A048374.

Programs

Mathematica

a[n_] := Module[{i = 0}, While[DigitCount[i^3][[7]] != n, i++ ]; i]; (* Sam Handler (sam_5_5_5_0(AT)yahoo.com), Aug 27 2006 *)

Extensions

a(14) from Sam Handler (sam_5_5_5_0(AT)yahoo.com), Aug 27 2006

a(15)-a(20) from Lars Blomberg, Jun 12 2011

a(21)-a(22) from Giovanni Resta, Jun 29 2018