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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 A257815

Adjacent sequences:  A029961 A029962 A029963 * A029965 A029966 A029967

KEYWORD

nonn,base,changed

AUTHOR

Patrick De Geest

STATUS

approved

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Last modified November 20 20:28 EST 2019. Contains 329347 sequences. (Running on oeis4.)