A048348 a(n)^2 is the smallest square containing exactly n 3's.
6, 56, 586, 1156, 11547, 57735, 559769, 1197219, 6582806, 36514844, 350903624, 1798230611, 1825769244, 48304278624, 11547014044, 577333277556, 1527394295306, 6582576498844, 57465931849517, 416333244448889, 581664313273844, 4820096824065156, 18256870415638994, 61913999493598646, 577694870440557344
Offset: 1
Links
- Eric Weisstein's World of Mathematics, Square Number
Programs
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Mathematica
a[n_] := Block[{k=1}, While[DigitCount[k^2, 10, 3] != n, k++]; k]; Array[a, 6] (* Giovanni Resta, Jul 27 2018 *)
Extensions
More terms from Jon E. Schoenfield, Jan 11 2009
a(18)-a(19) from Giovanni Resta, Jul 27 2018
a(20)-a(25) from Max Alekseyev, Mar 06 2025