A115668 - OEIS

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A115668

Brilliant numbers (A078972) whose digit reversal is a square.

4, 9, 10, 121, 169, 961, 1273, 1843, 10201, 10609, 12769, 16171, 44521, 48361, 48613, 94249, 96721, 106009, 108853, 121879, 129307, 445051, 526567, 613927, 1026169, 1042441, 1062961, 1216609, 1442401, 1692601

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Table of n, a(n) for n=1..30.

EXAMPLE

1843=19*97 is brilliant and 3481=59^2 is a square.

MATHEMATICA

brilQ[n_]:=Module[{fin=FactorInteger[n]}, Total[Transpose[fin][[2]]]==2&& Length[Union[IntegerLength[Transpose[fin][[1]]]]]==1]

brilnos=Select[Range[1700000], brilQ];

Select[brilnos, IntegerQ[Sqrt[FromDigits[Reverse[IntegerDigits[#]]]]]&] (* Harvey P. Dale, Feb 06 2011 *)

CROSSREFS

Cf. A078972, A115667, A115669.

Sequence in context: A082749 A220427 A115675 * A055675 A000974 A291626

Adjacent sequences: A115665 A115666 A115667 * A115669 A115670 A115671

KEYWORD

nonn,base

AUTHOR

Giovanni Resta, Jan 31 2006

STATUS

approved