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A029964
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Palindromic in bases 7 and 10.
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41
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0, 1, 2, 3, 4, 5, 6, 8, 121, 171, 242, 292, 16561, 65656, 2137312, 4602064, 6597956, 6958596, 9470749, 61255216, 230474032, 466828664, 485494584, 638828836, 657494756, 858474858, 25699499652, 40130703104, 45862226854
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OFFSET
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1,3
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LINKS
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MATHEMATICA
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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 *)
Select[Range[0, 10^5],
PalindromeQ[#] && # == IntegerReverse[#, 7] &] (* Robert Price, Nov 09 2019 *)
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CROSSREFS
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Cf. A007632, A007633, A029804, A029961, A029962, A029963, A029965, A029966, A029967, A029968, A029969, A029970.
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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