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A052049 a(n)^2 is a square whose digits occur with an equal minimum frequency of 2. 13
88, 478, 577, 583, 715, 836, 880, 881, 893, 3362, 3386, 3911, 4077, 4780, 5077, 5239, 5369, 5770, 5784, 5789, 5830, 5858, 6523, 6756, 6772, 6926, 6941, 7107, 7150, 7359, 7535, 7827, 8043, 8196, 8229, 8360, 8525, 8810, 8930, 8989, 9251, 9701, 9764, 9786 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Nathaniel Johnston, Table of n, a(n) for n = 1..5000

P. De Geest, Numbers whose digits occur with same frequency

EXAMPLE

577^2 = 332929, which contains each of its digits (2, 3, and 9) twice, so 577 is in this sequence.

MAPLE

isA052049 := proc(n) local d, k, fr, eqfr: d:=convert(n^2, base, 10): eqfr:=true: fr:=numboccur(d[1], d): if(fr=1)then return false: fi: for k from 0 to 9 do if(not member(numboccur(k, d), {fr, 0}))then eqfr:=false: break: fi: od: return eqfr: end: seq(`if`(isA052049(n), n, NULL), n=1..9800); # Nathaniel Johnston, Jun 02 2011

MATHEMATICA

ta[n_]:=DeleteDuplicates[Transpose[Tally[IntegerDigits[n^2]]][[2]]]; t ={}; Do[If[Length[x=ta[n]]==1 && x[[1]]>=2, AppendTo[t, n]], {n, 9800}]; t (* Jayanta Basu, May 11 2013 *)

CROSSREFS

Cf. A045540, A052046-A052048, A052050-A052052.

Sequence in context: A116065 A234777 A234770 * A046378 A187176 A236009

Adjacent sequences:  A052046 A052047 A052048 * A052050 A052051 A052052

KEYWORD

nonn,base

AUTHOR

Patrick De Geest, Dec 15 1999

STATUS

approved

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Last modified March 25 01:30 EDT 2017. Contains 284036 sequences.