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A030075 Squares which are palindromes in base 15. 11
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
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
Sequence in context: A368891 A073723 A161493 * A296111 A038784 A038239
KEYWORD
base,nonn
AUTHOR
STATUS
approved

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Last modified March 19 04:58 EDT 2024. Contains 370952 sequences. (Running on oeis4.)