A036511 Smallest square containing exactly n 4's.

4, 144, 1444, 44944, 6441444, 47444544, 4434494464, 44424414441, 4243443441444, 44844344414464, 444431244445444, 44044624434444544, 441544444344443449, 14444545446449449444, 346454444084444444644, 44024844440444424044544, 444448493447444044441744

Offset: 1

Author

David W. Wilson

Keywords

• nonn
• base

Comments

a(21) > 10^28. - Giovanni Resta, Jul 27 2018

Links

• Giovanni Resta, Table of n, a(n) for n = 1..20

Crossrefs

Cf. A048349. - Jon E. Schoenfield, Jan 24 2009

Programs

Mathematica

a[n_] := Block[{k=1}, While[DigitCount[k^2, 10, 4] != n, k++]; k^2]; Array[a, 7] (* Giovanni Resta, Jul 27 2018 *)

Extensions

a(13)-a(16) from Jon E. Schoenfield, Jan 17 2009

a(17) from Giovanni Resta, Jul 27 2018