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A179803 Numbers that contain the digital reverse of their square root. 2
1, 25, 36, 729, 5476, 927369, 32752729, 37724164, 42562576, 97357689, 2825135104, 4325166756, 4860041796, 123715399824, 167904077121, 247679410276, 389724269841, 442094669604, 486004179600, 610118772201, 7473372660009, 15049783154025, 23983713798489, 25315841305225 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
Giovanni Resta, Table of n, a(n) for n = 1..97 (terms < 1.6*10^25)
FORMULA
a(n) = A115761(n)^2.
EXAMPLE
The square root of 729 is 27. 27's digital reverse is 72. 72 appears in 729.
MATHEMATICA
fQ[n_] := StringPosition[ IntegerString[n^2], StringReverse@ IntegerString@ n] != {}; k = 1; lst = {}; While[k < 3879404, If[ fQ@k, AppendTo[lst, k^2]]; k++ ]; lst (* Robert G. Wilson v, Jul 28 2010 *)
drsrQ[n_]:=Module[{s=Sqrt[n]}, MemberQ[Partition[Reverse[ IntegerDigits[ n]], IntegerLength[ s], 1], IntegerDigits[s]]]; Select[Range[ 28*10^5]^2, drsrQ] (* Harvey P. Dale, Dec 15 2015 *)
CROSSREFS
Cf. A115761.
Sequence in context: A030681 A167363 A035383 * A061863 A079270 A253025
KEYWORD
nonn,base
AUTHOR
Dominick Cancilla, Jul 27 2010
EXTENSIONS
More terms from Robert G. Wilson v, Jul 28 2010
Terms a(22) and beyond from Giovanni Resta, May 04 2020
STATUS
approved

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Last modified July 12 15:21 EDT 2024. Contains 374251 sequences. (Running on oeis4.)