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.

Showing 1-10 of 12 results. Next

A060879 Intrinsic 9-palindromes: n is an intrinsic k-palindrome if it is a k-digit palindrome in some base.

Original entry on oeis.org

257, 273, 297, 313, 325, 341, 365, 381, 387, 403, 427, 443, 455, 471, 495, 511, 6562, 6643, 6724, 6832, 6913, 6994, 7102, 7183, 7264, 7300, 7381, 7462, 7570, 7651, 7732, 7840, 7921, 8002, 8038, 8119, 8200, 8308, 8389, 8470, 8578, 8659
Offset: 1

Views

Author

Harvey P. Dale, May 05 2001

Keywords

Comments

All numbers are intrinsic 1- and (for n>2) 2-palindromes, almost all numbers are intrinsic 3-palindromes and very few numbers are intrinsic k-palindromes for k >= 4. - Franklin T. Adams-Watters, Jul 29 2011

Crossrefs

A060947 Intrinsic 10-palindromes: n is an intrinsic k-palindrome if it is a k-digit palindrome in some base.

Original entry on oeis.org

513, 561, 585, 633, 645, 693, 717, 765, 771, 819, 843, 891, 903, 951, 975, 1023, 19684, 20008, 20332, 20440, 20764, 21088, 21196, 21520, 21844, 21880, 22204, 22528, 22636, 22960, 23284, 23392, 23716, 24040, 24076, 24400, 24724, 24832
Offset: 1

Views

Author

Harvey P. Dale, May 08 2001

Keywords

Comments

See A060873 for more information.

Crossrefs

Programs

  • Mathematica
    testQ[n_, k_] := For[b = 2, b <= Ceiling[(n-1)^(1/(k-1))], b++, d = IntegerDigits[n, b]; If[Length[d] == k && d == Reverse[d], Return[True]]]; n0[k_] := 2^(k-1) + 1; Reap[Do[If[testQ[n, 10] === True, Print[n, " ", FromDigits[d], " b = ", b]; Sow[n]], {n, n0[10], 25000}]][[2, 1]] (* Jean-François Alcover, Nov 07 2014 *)

A060949 Intrinsic 12-palindromes: n is an intrinsic k-palindrome if it is a k-digit palindrome in some base.

Original entry on oeis.org

2049, 2145, 2193, 2289, 2313, 2409, 2457, 2553, 2565, 2661, 2709, 2805, 2829, 2925, 2973, 3069, 3075, 3171, 3219, 3315, 3339, 3435, 3483, 3579, 3591, 3687, 3735, 3831, 3855, 3951, 3999, 4095, 177148, 178120, 179092, 179416, 180388
Offset: 1

Views

Author

Harvey P. Dale, May 08 2001

Keywords

Comments

See A060873 for more information.

Crossrefs

A060874 Intrinsic 4-palindromes: n is an intrinsic k-palindrome if it is a k-digit palindrome in some base.

Original entry on oeis.org

9, 15, 28, 40, 52, 56, 65, 68, 80, 85, 105, 125, 126, 130, 150, 156, 170, 186, 190, 195, 215, 216, 217, 235, 246, 252, 255, 259, 282, 301, 312, 342, 343, 344, 372, 378, 385, 400, 408, 427, 434, 438, 456, 468, 476, 498, 504, 512, 513, 518, 534
Offset: 1

Views

Author

Harvey P. Dale, May 05 2001

Keywords

Comments

All numbers are intrinsic 1- and 2-palindromes, almost all numbers are intrinsic 3-palindromes and very few numbers are intrinsic k-palindromes for k >= 4.

Crossrefs

Programs

  • Maple
    N:= 10^4: # to get all terms <= N
    S:= {}:
    for b from 2 to floor(N^(1/3)) do
      S:= S union {seq(seq((b^3+1)*i+(b^2+b)*j,j=0..b-1),i=1..b-1)}
    od:
    sort(convert(select(`<=`,S,N),list)); # Robert Israel, May 23 2016

A060875 Intrinsic 5-palindromes: n is an intrinsic k-palindrome if it is a k-digit palindrome in some base.

Original entry on oeis.org

17, 21, 27, 31, 82, 91, 100, 112, 121, 130, 142, 151, 160, 164, 173, 182, 194, 203, 212, 224, 233, 242, 257, 273, 289, 305, 325, 341, 357, 373, 393, 409, 425, 441, 461, 477, 493, 509, 514, 530, 546, 562, 582, 598, 614, 626, 630, 650, 651, 666
Offset: 1

Views

Author

Harvey P. Dale, May 05 2001

Keywords

Comments

All numbers are intrinsic 1- and 2-palindromes, almost all numbers are intrinsic 3-palindromes and very few numbers are intrinsic k-palindromes for k >= 4.

Crossrefs

A060876 Intrinsic 6-palindromes: n is an intrinsic k-palindrome if it is a k-digit palindrome in some base.

Original entry on oeis.org

33, 45, 51, 63, 244, 280, 316, 328, 364, 400, 412, 448, 484, 488, 524, 560, 572, 608, 644, 656, 692, 728, 1025, 1105, 1185, 1265, 1285, 1365, 1445, 1525, 1545, 1625, 1705, 1785, 1805, 1885, 1965, 2045, 2050, 2130, 2210, 2290, 2310, 2390
Offset: 1

Views

Author

Harvey P. Dale, May 05 2001

Keywords

Comments

All numbers are intrinsic 1- and 2-palindromes, almost all numbers are intrinsic 3-palindromes and very few numbers are intrinsic k-palindromes for k >= 4.

Crossrefs

A060877 Intrinsic 7-palindromes: n is an intrinsic k-palindrome if it is a k-digit palindrome in some base.

Original entry on oeis.org

65, 73, 85, 93, 99, 107, 119, 127, 730, 757, 784, 820, 847, 874, 910, 937, 964, 976, 1003, 1030, 1066, 1093, 1120, 1156, 1183, 1210, 1222, 1249, 1276, 1312, 1339, 1366, 1402, 1429, 1456, 1460, 1487, 1514, 1550, 1577, 1604, 1640, 1667, 1694
Offset: 1

Views

Author

Harvey P. Dale, May 05 2001

Keywords

Comments

All numbers are intrinsic 1- and 2-palindromes, almost all numbers are intrinsic 3-palindromes and very few numbers are intrinsic k-palindromes for k >= 4.

Crossrefs

A060878 Intrinsic 8-palindromes: n is an intrinsic k-palindrome if it is a k-digit palindrome in some base.

Original entry on oeis.org

129, 153, 165, 189, 195, 219, 231, 255, 2188, 2296, 2404, 2440, 2548, 2656, 2692, 2800, 2908, 2920, 3028, 3136, 3172, 3280, 3388, 3424, 3532, 3640, 3652, 3760, 3868, 3904, 4012, 4120, 4156, 4264, 4372, 4376, 4484, 4592, 4628, 4736, 4844
Offset: 1

Views

Author

Harvey P. Dale, May 05 2001

Keywords

Comments

All numbers are intrinsic 1- and 2-palindromes, almost all numbers are intrinsic 3-palindromes and very few numbers are intrinsic k-palindromes for k >= 4.

Crossrefs

A060948 Intrinsic 11-palindromes: n is an intrinsic k-palindrome if it is a k-digit palindrome in some base.

Original entry on oeis.org

1025, 1057, 1105, 1137, 1161, 1193, 1241, 1273, 1285, 1317, 1365, 1397, 1421, 1453, 1501, 1533, 1539, 1571, 1619, 1651, 1675, 1707, 1755, 1787, 1799, 1831, 1879, 1911, 1935, 1967, 2015, 2047, 59050, 59293, 59536, 59860, 60103, 60346
Offset: 1

Views

Author

Harvey P. Dale, May 08 2001

Keywords

Comments

See A060873 for more information.

Crossrefs

A114255 Numbers that are nontrivial (3 digits or more) palindromes when expressed in some base 2 or greater.

Original entry on oeis.org

5, 7, 9, 10, 13, 15, 16, 17, 20, 21, 23, 25, 26, 27, 28, 29, 31, 33, 34, 36, 37, 38, 40, 41, 42, 43, 45, 46, 49, 50, 51, 52, 55, 56, 57, 59, 61, 62, 63, 64, 65, 67, 68, 71, 72, 73, 74, 78, 80, 81, 82, 83, 85, 86, 88, 89, 91, 92, 93, 97, 98, 99, 100, 101, 104, 105, 107, 109
Offset: 1

Views

Author

Jason Orendorff (jason.orendorff(AT)gmail.com), Feb 05 2006

Keywords

Comments

All integers are trivially palindromes in base 1. All integers n>2 are trivially 2-digit palindromes because they can be represented as "11" in base n-1.

Examples

			5 is present because the palindrome (101 base 2) = 5; 803 is present because (30203 base 4) = 803.
		

Crossrefs

Programs

  • Haskell
    isPalindrome s = (s == reverse s) digits 0 _ = [] digits n b = n `rem` b : digits (n `quot` b) b check n = any isPalindrome $ takeWhile (\x -> length x > 2) $ map (digits n) [2..] main = mapM print $ filter check [1..]
    
  • Mathematica
    palindromeQ[n_, b_] := (id = IntegerDigits[n, b]) === Reverse[id] && Length[id] >= 3; palindromeQ[n_] := Or @@ (palindromeQ[n, #] & ) /@ Range[2, n-2]; Select[ Range[110], palindromeQ] (* Jean-François Alcover, Dec 16 2011 *)
  • PARI
    isok(n) = for (b=2, n-1, if ((d=digits(n,b)) && (#d >= 3) && (Vecrev(d) == d), return (1));); \\ Michel Marcus, Jul 28 2016

Extensions

Cross-references from Charles R Greathouse IV, Aug 04 2010
Showing 1-10 of 12 results. Next