A048350 a(n)^2 is the smallest square containing exactly n 5's.

5, 75, 235, 745, 22485, 22925, 235065, 505525, 2356384, 23569166, 227069495, 674919666, 3931354166, 7450205075, 39969432765, 524933839166, 2134374738666, 4904646324166, 23802428354166, 159861050770834, 725227930760773, 1882963768916666, 7586668936732745, 74536940878685015, 174801474694453186

Offset

1,1

Links

Table of n, a(n) for n=1..25.

Eric Weisstein's World of Mathematics, Square Number

Mathematica

k := 1; For[n = 1, n < 30000, n++, If[DigitCount[n^2][[5]] == k, k++; Print[n]]] (* Stefan Steinerberger, Apr 09 2006 *)
a[n_] := Module[{i = 1}, While[DigitCount[i^2][[6]] != n, i++; ]; i]; (* Sam Handler (sam_5_5_5_0(AT)yahoo.com), Aug 20 2006 *)

Crossrefs

Cf. A036512, A034986, A048351.

Sequence in context: A156703 A380925 A285452 * A030991 A216093 A151752

Adjacent sequences: A048347 A048348 A048349 * A048351 A048352 A048353

Keyword

nonn,base,changed

Author

Patrick De Geest, Mar 15 1999

Extensions

More terms from Jon E. Schoenfield, Jan 14 2009

One more term from Jon E. Schoenfield, Jan 25 2009

a(17)-a(19) from Giovanni Resta, Jul 27 2018

a(20)-a(25) from Max Alekseyev, Mar 06 2025

Status

approved