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 A029964 Palindromic in bases 7 and 10. 40
 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 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS Robert G. Wilson v, Table of n, a(n) for n = 1..65 P. De Geest, Palindromic numbers beyond base 10 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, 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 *) CROSSREFS Cf. A007632, A007633, A029804, A029961, A029962, A029963, A029965, A029966, A029967, A029968, A029969, A029970. Sequence in context: A128421 A115885 A259390 * A275583 A295088 A332990 Adjacent sequences:  A029961 A029962 A029963 * A029965 A029966 A029967 KEYWORD nonn,base AUTHOR STATUS approved

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Last modified October 25 15:14 EDT 2020. Contains 338012 sequences. (Running on oeis4.)