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A030075 Squares which are palindromes in base 15. 9
0, 1, 4, 9, 16, 64, 144, 256, 361, 1024, 1521, 4096, 5776, 16384, 20736, 51076, 58081, 65536, 73441, 96721, 204304, 218089, 228484, 232324, 331776, 511225, 817216, 929296, 1048576, 3055504, 3268864, 3489424, 5308416, 7033104 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..106

Patrick De Geest, Palindromic Squares

EXAMPLE

8^2 = 64, which in base 15 is 44, and that's palindromic, so 64 is in the sequence.

9^2 = 81, which in base 15 is 56. Since that's not palindromic, 81 is not in the sequence.

MAPLE

N:= 10^10: # to get all entries <= N

count:= 0:

for x from 0 to floor(sqrt(N)) do

    y:= x^2;

    L:= convert(y, base, 15);

  if ListTools[Reverse](L) = L then

     count:= count+1;

     A[count]:= y;

   fi

od:

seq(A[i], i=1..count); # Robert Israel, Jul 24 2014

MATHEMATICA

palQ[n_, b_:10] := Module[{idn = IntegerDigits[n, b]}, idn == Reverse[idn]]; Select[Range[0, 2700]^2, palQ[#, 15] &]  (* Harvey P. Dale, Apr 23 2011 *)

PROG

(PARI) isok(n) = my(d=digits(n, 15)); issquare(n) && (d == Vecrev(d)); \\ Michel Marcus, Oct 21 2016

CROSSREFS

Cf. A002779, A029734, A029738, A029806, A029983, A029985, A029987, A029989, A029991, A029993, A029995, A029997, A029999, A030074.

Sequence in context: A277699 A073723 A161493 * A038784 A038239 A263094

Adjacent sequences:  A030072 A030073 A030074 * A030076 A030077 A030078

KEYWORD

base,nonn

AUTHOR

Patrick De Geest

STATUS

approved

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Last modified August 22 06:50 EDT 2017. Contains 290942 sequences.