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.

A319598 Numbers in base 10 that are palindromic in bases 2, 4, 8, and 16.

Original entry on oeis.org

0, 1, 3, 5, 4095, 4097, 12291, 20485, 21845, 16777215, 16777217, 16781313, 50331651, 50343939, 83886085, 83906565, 89458005, 89478485, 68702703615, 68719476735, 68719476737, 68736258049, 206158430211, 206208774147, 343597383685, 343602954245, 343681290245
Offset: 1

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Author

Jeremias M. Gomes, Sep 24 2018

Keywords

Comments

Intersection of A006995, A014192, A029803, and A029730.
This sequence is infinite because it contains terms of the forms 4096^k-1 (k>=0) and 4096^k+1 (k>0). - Bruno Berselli, Sep 24 2018

Examples

			4095 = 111111111111_2 = 333333_4 = 7777_8 = FFF_16. Hence 4095 is in the sequence.
		

Crossrefs

Cf. A006995 (base 2), A014192 (base 4), A029803 (base 8), and A029730 (base 16).

Programs

  • Mathematica
    palQ[n_, b_] := PalindromeQ[IntegerDigits[n, b]];
    Reap[Do[If[palQ[n, 2] && palQ[n, 4] && palQ[n, 8] && palQ[n, 16], Print[n]; Sow[n]], {n, 0, 10^6}]][[2, 1]] (* Jean-François Alcover, Sep 25 2018 *)
  • Sage
    [n for n in (0..100000) if Word(n.digits(2)).is_palindrome() and Word(n.digits(4)).is_palindrome() and Word(n.digits(8)).is_palindrome() and Word(n.digits(16)).is_palindrome()]

Extensions

a(19)-a(27) from Rémy Sigrist, Nov 15 2018