A036514 Smallest square containing exactly n 7's.

576, 5776, 179776, 12787776, 77774761, 7907477776, 77770707876, 4477777637776, 77777477275716, 3777771174707776, 76978737777779776, 276767777777770756, 3777077879777771776, 477772772701777877776, 39877777877357777777476, 67777770773777677177744

Offset

1,1

Comments

a(20) > 10^28. - Giovanni Resta, Jul 27 2018

Links

Giovanni Resta, Table of n, a(n) for n = 1..19

Mathematica

a[n_] := Block[{k=1}, While[DigitCount[k^2, 10, 7] != n, k++]; k]; Array[a, 6] (* Giovanni Resta, Jul 27 2018 *)

Crossrefs

Cf. A048352. - Jon E. Schoenfield, Jan 24 2009

Sequence in context: A067225 A325475 A268797 * A269034 A188787 A235738

Adjacent sequences: A036511 A036512 A036513 * A036515 A036516 A036517

Keyword

nonn,base

Author

David W. Wilson

Extensions

More terms from Jon E. Schoenfield, Jan 24 2009

a(16) from Giovanni Resta, Jul 27 2018

Status

approved