A034992 -id:A034992 - cp's OEIS frontend

A048353 a(n)^2 is the smallest square containing exactly n 8's.

9, 83, 298, 1378, 8878, 29641, 298141, 623609, 9321378, 28072917, 94121667, 329877083, 4341484641, 29478276559, 62360956378, 151284113141, 3436394751609, 9428037062872, 22065558748622, 29770520349641, 942808510191167, 9427024391927083, 22335822988837615, 94270265131105359, 298125621993127083

Offset: 1

Patrick De Geest, Mar 15 1999

Eric Weisstein's World of Mathematics, Square Number

Cf. A036515, A034992.

a[n_] := Module[{i = 1}, While[DigitCount[i^2][[8]] != n, i++ ]; i]; (* Sam Handler (sam_5_5_5_0(AT)yahoo.com), Aug 22 2006 *)

a(13)-a(16) from Jon E. Schoenfield, Jan 24 2009
a(17)-a(20) from Giovanni Resta, Jul 27 2018
a(21)-a(25) from Max Alekseyev, Mar 06 2025

A034993 Smallest square starting with a string of n 8's.

Original entry on oeis.org

81, 8836, 88804, 88887184, 88888055881, 888888810481, 888888810481, 8888888859057216, 88888888888905609, 88888888888905609, 88888888888905609, 888888888888769405062724, 888888888888817576082400016, 8888888888888825421477138436, 888888888888888199001963335969, 888888888888888832115283007868025

Offset: 1

Patrick De Geest, Nov 15 1998

Robert Israel, Table of n, a(n) for n = 1..300

Cf. A034992.

f:= proc(n) local q, k, x;
  q:= 8*(10^n-1)/9;
  for k from 0 do
    x:= ceil(sqrt(q*10^k));
    if x^2 < (q+1)*10^k then return x^2 fi
  od
end proc:
map(f, [$1..20]); # Robert Israel, Jun 26 2018

More terms from Robert Israel, Jun 26 2018

cp's OEIS Frontend

A048353 a(n)^2 is the smallest square containing exactly n 8's.

Views

Author

Keywords

Links

Crossrefs

Programs

Mathematica

Extensions