A048354 - OEIS

%I #20 Mar 06 2025 10:54:02

%S 3,63,173,1414,17313,53937,138923,953937,3082207,31622764,99849687,

%T 301579177,3033150173,14142134563,141413973847,543315746063,

%U 3098361825223,5477225574409,14139412282687,314896807700437,412286308285783,3147904051904219,9055381813816577,311447546136054827,282841298257395573

%N a(n)^2 is the smallest square containing exactly n 9's.

%H Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/SquareNumber.html">Square Number</a>

%t a[n_]:=Module[{i},i=1;While[DigitCount[i^2][[9]]!=n,i++ ];i]; (* Sam Handler (sam_5_5_5_0(AT)yahoo.com), Aug 23 2006 *)

%Y Cf. A036516, A034994.

%K nonn,base,changed

%O 1,1

%A _Patrick De Geest_, Mar 15 1999

%E a(13)-a(15) from _Jon E. Schoenfield_, Jan 24 2009

%E a(16) from _Jon E. Schoenfield_, Jan 25 2009

%E a(17)-a(19) from _Giovanni Resta_, Jul 27 2018

%E a(20)-a(25) from _Max Alekseyev_, Mar 06 2025