A029986 Numbers k such that k^2 is palindromic in base 4.
0, 1, 5, 17, 21, 65, 71, 83, 257, 273, 281, 317, 1025, 1055, 4097, 4161, 4193, 4401, 5157, 5179, 5221, 16385, 16511, 16865, 17239, 65537, 65793, 65921, 66753, 68695, 69521, 69777, 80739, 82053, 82171, 82309, 82885, 83301, 262145
Offset: 1
Links
- Seiichi Manyama, Table of n, a(n) for n = 1..100
- Patrick De Geest, Palindromic Squares in bases 2 to 17
Crossrefs
Numbers k such that k^2 is palindromic in base b: A003166 (b=2), A029984 (b=3), this sequence (b=4), A029988 (b=5), A029990 (b=6), A029992 (b=7), A029805 (b=8), A029994 (b=9), A002778 (b=10), A029996 (b=11), A029737 (b=12), A029998 (b=13), A030072 (b=14), A030073 (b=15), A029733 (b=16), A118651 (b=17).
Programs
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Mathematica
Select[Range[0,300000],IntegerDigits[#^2,4]==Reverse[ IntegerDigits[ #^2,4]]&] (* Harvey P. Dale, Dec 01 2015 *)
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PARI
isok(k) = my(d=digits(k^2,4)); d == Vecrev(d); \\ Michel Marcus, Jul 04 2021
Comments