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A029961 Palindromic in bases 4 and 10. 40
0, 1, 2, 3, 5, 55, 373, 393, 666, 787, 939, 7997, 53235, 55255, 55655, 57675, 506605, 1801081, 2215122, 3826283, 3866683, 5051505, 5226225, 5259525, 5297925, 5614165, 5679765, 53822835, 623010326, 954656459, 51717171715 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Robert G. Wilson v, Table of n, a(n) for n = 1..56

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, 4], AppendTo[l, a]], {n, 1000000}]; l (* Robert G. Wilson v, Sep 30 2004 *)

CROSSREFS

Cf. A007632, A007633, A029962, A029963, A029964, A029804, A029965, A029966, A029967, A029968, A029969, A029970, A029731, A097855, A099165.

Sequence in context: A114370 A114725 A136340 * A083665 A214752 A238201

Adjacent sequences:  A029958 A029959 A029960 * A029962 A029963 A029964

KEYWORD

nonn,base

AUTHOR

Patrick De Geest

STATUS

approved

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Last modified June 29 12:13 EDT 2017. Contains 288860 sequences.