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 A074836 a(1) = 1, a(n) = the largest prime divisor of concatenation of sequence (n,n-1,..,2,1,2,..,n-1,n) A007942. 0
 53, 353, 2160617, 479, 146053847, 18533465459, 18588601, 444444443, 10987654321234567891, 41824630287288128897, 24899126702236725259, 131211109876543212345678910111213, 59722151033999393, 1081735780698166140181, 40378532802777469135803086419727527803285379 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,1 LINKS M. Fleuren, Smarandache Mirror Sequence. EXAMPLE a(4) is 2160617 because 4321234 = 2.'2160617'. MATHEMATICA Table[FactorInteger[FromDigits[Join[Flatten[IntegerDigits/@ Range[ n, 1, -1]], Flatten[IntegerDigits/@Range[2, n]]]]][[-1, 1]], {n, 2, 15}] (* Harvey P. Dale, Sep 05 2015 *) CROSSREFS Cf. A007942. Sequence in context: A174441 A094249 A244771 * A142851 A185239 A053736 Adjacent sequences:  A074833 A074834 A074835 * A074837 A074838 A074839 KEYWORD nonn,base AUTHOR Jason Earls, Sep 09 2002 EXTENSIONS Edited by Charles R Greathouse IV, Apr 28 2010 More terms from Harvey P. Dale, Sep 05 2015 STATUS approved

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Last modified June 22 07:09 EDT 2021. Contains 345374 sequences. (Running on oeis4.)