A029969 Numbers that are palindromic in bases 10 and 14.

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 323, 464, 717, 858, 999, 1111, 39593, 59095, 420024, 546645, 9046409, 9578759, 9813189, 535505535, 564303465, 595121595, 5736116375, 6758008576, 10476867401, 11652825611, 14203330241

Offset: 1

Author

Patrick De Geest

Keywords

• nonn
• base

Links

• Robert G. Wilson v, Table of n, a(n) for n = 1..70 (first 63 terms from Ray Chandler)
• P. De Geest, Palindromic numbers beyond base 10

Crossrefs

Cf. A007632, A007633, A029961, A029962, A029963, A029964, A029804, A029965, A029966, A029967, A029968, A029970, A029731, A097855, A099165.

Programs

Magma

[n: n in [0..10000000] | Intseq(n, 10) eq Reverse(Intseq(n, 10))and Intseq(n, 14) eq Reverse(Intseq(n, 14))]; // Vincenzo Librandi, Nov 23 2014

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, 14], AppendTo[l, a]], {n, 300000}]; l (* Robert G. Wilson v, Sep 03 2004 *)
b1=10; b2=14; lst={}; Do[d1=IntegerDigits[n, b1]; d2=IntegerDigits[n, b2]; If[d1==Reverse[d1]&&d2==Reverse[d2], AppendTo[lst, n]], {n, 0, 1000000}]; lst (* Vincenzo Librandi, Nov 23 2014 *)
palQ[n_]:=Module[{idn14=IntegerDigits[n,14]},n==IntegerReverse[n]&&idn14==Reverse[idn14]]; Select[Range[10^7],palQ] (* The program uses the IntegerReverse function from Mathematica version 10 *) (* Harvey P. Dale, Apr 23 2016 *)
Select[Range[0, 10^5],
PalindromeQ[#] && # == IntegerReverse[#, 14] &] (* Robert Price, Nov 09 2019 *)