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 A262039 Nearest palindrome to n; in case of a tie choose the larger palindrome. 2
 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 11, 11, 11, 11, 11, 11, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 33, 33, 33, 33, 33, 33, 33, 33, 33, 33, 33, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 55, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 66, 77, 77 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS In analogy to the numerical "round" function, we "round up" to the next larger palindrome A262038(n) if it is at the same distance or closer, else we "round down" to the next smaller palindrome A261423(n). See A262040 for a variant where the next smaller palindrome is chosen in case of equal distance. LINKS Table of n, a(n) for n=0..73. EXAMPLE a(10) = 11 since we round up if the next smaller palindrome (here 9) is at the same distance, both 9 and 11 are here at distance 1 from n = 10. a(16) = 11 since |16 - 11| = 5 is smaller than |16 - 22| = 6. a(17) = 22 since |17 - 22| = 5 is smaller than |17 - 11| = 6. a(27) = 22 since |22 - 27| = 5 is smaller than |27 - 33| = 6. a(28) = 33 since |33 - 28| = 5 is smaller than |22 - 28| = 6, and so on. a(100) = 101 because we round up again in this case, where 99 and 101 both are at distance 1 from n = 100. MATHEMATICA palQ[n_] := Block[{d = IntegerDigits@ n}, d == Reverse@ d]; f[n_] := Block[{k = n}, While[Nand[palQ@ k, k > -1], k--]; k]; g[n_] := Block[{k = n}, While[! palQ@ k, k++]; k]; h[n_] := Block[{a = f@ n, b = g@ n}, Which[palQ@ n, n, (b - n) - (n - a) > 0, a, (b - n) - (n - a) <= 0, b]]; Table[h@ n, {n, 0, 73}] (* Michael De Vlieger, Sep 09 2015 *) CROSSREFS Cf. A002113, A261423, A262037, A262038, A262040. Sequence in context: A065649 A338830 A262037 * A354719 A340835 A123241 Adjacent sequences: A262036 A262037 A262038 * A262040 A262041 A262042 KEYWORD nonn,base AUTHOR M. F. Hasler, Sep 08 2015 STATUS approved

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Last modified October 4 15:42 EDT 2023. Contains 365885 sequences. (Running on oeis4.)