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 A048349 a(n)^2 is the smallest square containing exactly n 4's. 1
 2, 12, 38, 212, 2538, 6888, 66592, 210771, 2059962, 6696592, 21081538, 209868112, 664488107, 3800598038, 18613286762, 209820981888, 666669703412, 666516649788, 6666894662768, 49400874945738 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(21) > 10^14. - Giovanni Resta, Jul 27 2018 LINKS Eric Weisstein's World of Mathematics, Square Number MATHEMATICA a[n_] := Block[{k=1}, While[DigitCount[k^2, 10, 4] != n, k++]; k]; Array[a, 7] (* Giovanni Resta, Jul 27 2018 *) CROSSREFS Cf. A036511, A034984. Sequence in context: A035597 A000913 A026575 * A009632 A190022 A086602 Adjacent sequences:  A048346 A048347 A048348 * A048350 A048351 A048352 KEYWORD nonn,base,more AUTHOR Patrick De Geest, Mar 15 1999 EXTENSIONS More terms from Jon E. Schoenfield, Jan 14 2009 a(17)-a(20) from Giovanni Resta, Jul 27 2018 STATUS approved

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Last modified August 2 06:52 EDT 2021. Contains 346411 sequences. (Running on oeis4.)