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A014192
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Palindromes in base 4 (written in base 10).
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32
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0, 1, 2, 3, 5, 10, 15, 17, 21, 25, 29, 34, 38, 42, 46, 51, 55, 59, 63, 65, 85, 105, 125, 130, 150, 170, 190, 195, 215, 235, 255, 257, 273, 289, 305, 325, 341, 357, 373, 393, 409, 425, 441, 461, 477, 493, 509, 514, 530, 546, 562, 582, 598, 614, 630, 650, 666
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,3
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COMMENTS
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Rajasekaran, Shallit, & Smith prove that this sequence is an additive basis of order (exactly) 3. - Charles R Greathouse IV, May 03 2020
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LINKS
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FORMULA
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Sum_{n>=2} 1/a(n) = 2.7857715... (Phunphayap and Pongsriiam, 2019). - Amiram Eldar, Oct 17 2020
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MATHEMATICA
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f[n_, b_] := Module[{i=IntegerDigits[n, b]}, i==Reverse[i]]; lst={}; Do[If[f[n, 4], AppendTo[lst, n]], {n, 1000}]; lst (* Vladimir Joseph Stephan Orlovsky, Jul 08 2009 *)
pal4Q[n_]:=Module[{c=IntegerDigits[n, 4]}, c==Reverse[c]]; Select[Range[ 0, 700], pal4Q] (* Harvey P. Dale, Jul 21 2020 *)
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PROG
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(Magma) [n: n in [0..800] | Intseq(n, 4) eq Reverse(Intseq(n, 4))]; // Vincenzo Librandi, Sep 09 2015
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CROSSREFS
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KEYWORD
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nonn,base,easy
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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