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.

A099165 Palindromic in bases 10 and 32.

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 22, 33, 66, 99, 363, 858, 1441, 2882, 5445, 6886, 9449, 15951, 19891, 21012, 29692, 32223, 54945, 369963, 477774, 564465, 585585, 609906, 672276, 717717, 780087, 804408, 912219, 1251521, 2639362, 3825283
Offset: 1

Views

Author

Robert G. Wilson v, Sep 30 2004

Keywords

Crossrefs

Programs

  • Mathematica
    NextPalindrome[n_] := Block[{l = Floor[ Log[10, n] + 1], idn = IntegerDigits[n]}, If[ Union[idn] == {9}, Return[n + 2], If[l < 2, Return[n + 1], If[ FromDigits[ Reverse[ Take[idn, Ceiling[l/2]] ]] FromDigits[ Take[idn, -Ceiling[l/2]]], FromDigits[ Join[ Take[idn, Ceiling[l/2]], Reverse[ Take[idn, Floor[l/2]] ]]], idfhn = FromDigits[ Take[idn, Ceiling[l/2]]] + 1; idp = FromDigits[ Join[ IntegerDigits[idfhn], Drop[ Reverse[ IntegerDigits[idfhn]], Mod[l, 2]] ]]] ]]]; palQ[n_Integer, base_Integer] := Block[{idn = IntegerDigits[n, base]}, idn == Reverse[idn]]; l = {0}; a = 0; Do[a = NextPalindrome[a]; If[ palQ[a, 32], AppendTo[l, a]], {n, 10000}]; l
    Select[Range[0, 10^5],
    PalindromeQ[#] && # == IntegerReverse[#, 32] &] (* Robert Price, Nov 09 2019 *)
  • Python
    from gmpy2 import digits
    def palQ(n,b): # check if n is a palindrome in base b
        s = digits(n,b)
        return s == s[::-1]
    def palQgen10(l): # unordered generator of palindromes of length <= 2*l
        if l > 0:
            yield 0
            for x in range(1,10**l):
                s = str(x)
                yield int(s+s[-2::-1])
                yield int(s+s[::-1])
    A099165_list = sorted([n for n in palQgen10(6) if palQ(n,32)])
    # Chai Wah Wu, Nov 25 2014