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A029964 Palindromic in bases 7 and 10. 40

%I

%S 0,1,2,3,4,5,6,8,121,171,242,292,16561,65656,2137312,4602064,6597956,

%T 6958596,9470749,61255216,230474032,466828664,485494584,638828836,

%U 657494756,858474858,25699499652,40130703104,45862226854

%N Palindromic in bases 7 and 10.

%H Robert G. Wilson v, <a href="/A029964/b029964.txt">Table of n, a(n) for n = 1..65</a>

%H P. De Geest, <a href="http://www.worldofnumbers.com/nobase10.htm">Palindromic numbers beyond base 10</a>

%t 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, 7], AppendTo[l, a]], {n, 2000000}]; l (* _Robert G. Wilson v_, Sep 30 2004 *)

%t Select[Range[0, 10^5],

%t PalindromeQ[#] && # == IntegerReverse[#, 7] &] (* _Robert Price_, Nov 09 2019 *)

%Y Cf. A007632, A007633, A029804, A029961, A029962, A029963, A029965, A029966, A029967, A029968, A029969, A029970.

%K nonn,base,changed

%O 1,3

%A _Patrick De Geest_

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Last modified November 15 13:47 EST 2019. Contains 329149 sequences. (Running on oeis4.)