cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A029805 Numbers k such that k^2 is palindromic in base 8.

Original entry on oeis.org

0, 1, 2, 3, 6, 9, 11, 27, 65, 73, 79, 81, 83, 195, 219, 237, 366, 513, 543, 585, 697, 1094, 1539, 1755, 1875, 2910, 4097, 4161, 4225, 4477, 4617, 4681, 4727, 4891, 5267, 8698, 8730, 11841, 12291, 12483, 12675, 13065, 13851, 14673, 15021
Offset: 1

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Keywords

Comments

The only powers of 2 in this sequence are 1 and 2. - Alonso del Arte, Feb 25 2017

Examples

			3 is in the sequence because 3^2 = 9 = 11 in base 8, which is a palindrome.
4 is not in the sequence because 4^2 = 16 = 20 in base 8, which is not a palindrome.
		

Crossrefs

Numbers k such that k^2 is palindromic in base b: A003166 (b=2), A029984 (b=3), A029986 (b=4), A029988 (b=5), A029990 (b=6), A029992 (b=7), this sequence (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

  • Mathematica
    palQ[n_, b_:10] := Module[{idn = IntegerDigits[n, b]}, idn == Reverse[idn]]; Select[Range[0, 16000], palQ[#^2, 8] &] (* Harvey P. Dale, May 19 2012 *)
  • Python
    from itertools import count, islice
    def A029805_gen(): # generator of terms
        return filter(lambda k: (s:=oct(k**2)[2:])[:(t:=(len(s)+1)//2)]==s[:-t-1:-1],count(0))
    A029805_list = list(islice(A029805_gen(),20)) # Chai Wah Wu, Jun 23 2022

A029994 Numbers k such that k^2 is palindromic in base 9.

Original entry on oeis.org

0, 1, 2, 10, 20, 82, 91, 100, 164, 730, 820, 1460, 6562, 6643, 6724, 7300, 7381, 7462, 13124, 13642, 13660, 14281, 54050, 59050, 59860, 65620, 66430, 118100, 123010, 126286, 161410, 161896, 487750, 531442, 532171
Offset: 1

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Crossrefs

Cf. A007095.
Numbers k such that k^2 is palindromic in base b: A003166 (b=2), A029984 (b=3), A029986 (b=4), A029988 (b=5), A029990 (b=6), A029992 (b=7), A029805 (b=8), this sequence (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

  • Mathematica
    pb9Q[n_]:=Module[{idn=IntegerDigits[n^2,9]},idn==Reverse[idn]]; Select[ Range[0,600000],pb9Q] (* Harvey P. Dale, Sep 29 2013 *)

A029996 Numbers k such that k^2 is palindromic in base 11.

Original entry on oeis.org

0, 1, 2, 3, 6, 12, 24, 26, 72, 84, 122, 133, 144, 244, 255, 279, 382, 732, 1332, 1464, 1596, 2414, 2664, 2796, 3062, 4476, 7992, 14642, 14763, 14884, 15984, 16105, 16226, 17326, 29284, 29405, 30626, 33675, 34701, 63546, 87246, 87852, 88578
Offset: 1

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Crossrefs

Numbers k such that k^2 is palindromic in base b: A003166 (b=2), A029984 (b=3), A029986 (b=4), A029988 (b=5), A029990 (b=6), A029992 (b=7), A029805 (b=8), A029994 (b=9), A002778 (b=10), this sequence (b=11), A029737 (b=12), A029998 (b=13), A030072 (b=14), A030073 (b=15), A029733 (b=16), A118651 (b=17).

A029737 Numbers whose square is palindromic in base 12.

Original entry on oeis.org

0, 1, 2, 3, 13, 26, 145, 157, 169, 179, 181, 290, 292, 302, 611, 1729, 1745, 1783, 1885, 2041, 3458, 3614, 3796, 20737, 20881, 21025, 21169, 22477, 22621, 22765, 24073, 24217, 24361, 24599, 25523, 25579, 28613, 41474, 41618, 41908, 43214
Offset: 1

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Crossrefs

Numbers k such that k^2 is palindromic in base b: A003166 (b=2), A029984 (b=3), A029986 (b=4), A029988 (b=5), A029990 (b=6), A029992 (b=7), A029805 (b=8), A029994 (b=9), A002778 (b=10), A029996 (b=11), this sequence (b=12), A029998 (b=13), A030072 (b=14), A030073 (b=15), A029733 (b=16), A118651 (b=17).

Programs

  • Mathematica
    pal12Q[n_]:=Module[{idn12=IntegerDigits[n^2,12]},idn12==Reverse[idn12]]
    Select[Range[0,50000],pal12Q]  (* Harvey P. Dale, Feb 06 2011 *)

A029998 Numbers k such that k^2 is palindromic in base 13.

Original entry on oeis.org

0, 1, 2, 3, 14, 28, 170, 183, 196, 209, 308, 340, 353, 366, 2198, 2380, 2562, 2898, 4026, 4242, 4396, 4578, 7078, 7662, 28562, 28731, 28900, 29069, 30772, 30941, 31110, 32813, 32982, 33151, 37374, 51510, 52360, 54942, 55449, 57124, 57293
Offset: 1

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Crossrefs

Numbers k such that k^2 is palindromic in base b: A003166 (b=2), A029984 (b=3), A029986 (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), this sequence (b=13), A030072 (b=14), A030073 (b=15), A029733 (b=16), A118651 (b=17).

A030072 Numbers k such that k^2 is palindromic in base 14.

Original entry on oeis.org

0, 1, 2, 3, 15, 24, 30, 47, 165, 197, 211, 225, 239, 394, 408, 422, 2190, 2445, 2745, 2955, 3165, 5490, 5700, 8565, 38417, 38613, 38809, 39005, 41175, 41371, 41567, 41763, 43737, 43933, 44129, 48159, 55962, 76834, 77030, 77226, 79592, 79788
Offset: 1

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Crossrefs

Numbers k such that k^2 is palindromic in base b: A003166 (b=2), A029984 (b=3), A029986 (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), this sequence (b=14), A030073 (b=15), A029733 (b=16), A118651 (b=17).

Programs

  • Mathematica
    pal14Q[n_]:=Module[{idn14=IntegerDigits[n^2,14]},idn14==Reverse[idn14]]; Select[Range[0,80000],pal14Q] (* Harvey P. Dale, Mar 09 2012 *)

A030073 Numbers k such that k^2 is palindromic in base 15.

Original entry on oeis.org

0, 1, 2, 3, 4, 8, 12, 16, 19, 32, 39, 64, 76, 128, 144, 226, 241, 256, 271, 311, 452, 467, 478, 482, 576, 715, 904, 964, 1024, 1748, 1808, 1868, 2304, 2652, 2860, 3376, 3401, 3616, 3856, 4639, 6752, 6992, 7172, 8649, 10715, 13504, 13604
Offset: 1

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Crossrefs

Numbers k such that k^2 is palindromic in base b: A003166 (b=2), A029984 (b=3), A029986 (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), this sequence (b=15), A029733 (b=16), A118651 (b=17).

Programs

  • Mathematica
    p15Q[n_]:=Module[{id15=IntegerDigits[n^2,15]},id15==Reverse[id15]]; Select[ Range[0,14000],p15Q] (* Harvey P. Dale, Jun 03 2020 *)

A263608 Palindromes which are base-3 representations of squares.

Original entry on oeis.org

0, 1, 11, 121, 10201, 11111, 112211, 122221, 1002001, 1120211, 11022011, 100020001, 101212101, 122111221, 1012112101, 1100220011, 10000200001, 10111011101, 110002200011, 111221122111, 1000002000001, 1001221221001, 1012200022101, 1101202021011, 1221221221221, 10101111110101
Offset: 1

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Author

N. J. A. Sloane, Oct 22 2015

Keywords

Crossrefs

Intersection of A001738 and A118594.

Programs

  • Maple
    rev3:= proc(n) local L,i; L:= convert(n,base,3); add(L[-i]*3^(i-1),i=1..nops(L)) end proc:
    c3:= proc(n) local L,i; L:= convert(n,base,3); add(L[i]*10^(i-1),i=1..nops(L)) end proc:
    R:= 0,1: count:= 2:
    for d from 2 while count < 100 do
        if d::odd then
          V:= select(issqr, [seq(seq(a*3^((d+1)/2) + b*3^((d-1)/2)+rev3(a),b=0..2),a=3^((d-3)/2) .. 3^((d-1)/2)-1)])
        else
          V:= select(issqr, [seq(a*3^(d/2) + rev3(a), a=3^(d/2-1) .. 3^(d/2)-1)]);
        fi;
        count:= count+nops(V);
        R:= R, op(map(c3,V));
    od:
    R; # Robert Israel, May 19 2024

Extensions

Name edited by Robert Israel, May 19 2024

A263612 Palindromes in base 5 which are also squares.

Original entry on oeis.org

0, 1, 4, 121, 10201, 12321, 114411, 1002001, 1234321, 100020001, 102030201, 121242121, 131141131, 10000200001, 10221412201, 12102420121, 131441144131, 1000002000001, 1002003002001, 1020304030201, 1143442443411, 1210024200121, 4133144413314, 4342230322434, 13431400413431, 100000020000001
Offset: 1

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Author

N. J. A. Sloane, Oct 23 2015

Keywords

Comments

Terms displayed in base 5. - Harvey P. Dale, Jan 10 2023

Crossrefs

Programs

  • Mathematica
    FromDigits[IntegerDigits[#,5]]&/@Select[Range[0,100000]^2,IntegerDigits[ #,5] == Reverse[ IntegerDigits[ #,5]]&] (* Harvey P. Dale, Jan 10 2023 *)

A229766 Odd numbers whose square's binary reversal is also a square.

Original entry on oeis.org

1, 3, 4523, 11991, 18197, 66075, 72225, 141683, 1092489, 3168099, 6001209, 6226335, 6435309, 12489657, 17906499, 50429883, 51928701, 68301841, 295742437, 390117873, 542959199, 554456167, 566494057
Offset: 1

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Author

Alex Ratushnyak, Dec 19 2013

Keywords

Comments

A003166 is a subsequence, except A003166(1)=0.
All odd numbers n such that A068527(A030101(n^2)) = 0. - Antti Karttunen, Dec 20 2013

Crossrefs

Formula

a(n) = sqrt(A229687(n)).
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