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 A113548 Least non-palindromic number k such that k and its digital reversal both have exactly n prime divisors. 1
 13, 12, 132, 1518, 15015, 204204, 10444434, 241879638, 20340535215, 242194868916 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS EXAMPLE a(1)=13=13 since 31=31, a(2)=12=2^2*3 since 21=3*7 a(3)=132=2^2*3*11 since 231=3*7*11 ... a(7)=10444434=2*3*7*11*13*37*47 since 43444401=3*7*11*13*17*23*37 a(8)=241879638=2*3*7*11*13*17*23*103 since 836978142=2*3*7*11*13*23*73*83 MATHEMATICA r[n_] := FromDigits[ Reverse[ IntegerDigits[ n]]]; f[n_] := Block[{k = r[n], len = Length[ FactorInteger[n]]}, If[k != n && len == Length[ FactorInteger[ r[n]]], len, 0]]; t = Table[0, {10}]; Do[ a = f[n]; If[a > 0 && t[[a]] == 0, t[[a]] = n; Print[{a, n}]], {n, 107}]; t CROSSREFS Cf. A110843, A110819. Sequence in context: A212526 A019331 A004454 * A249998 A195210 A175850 Adjacent sequences:  A113545 A113546 A113547 * A113549 A113550 A113551 KEYWORD base,hard,nonn AUTHOR Ryan Propper and Robert G. Wilson v, Sep 21 2005 EXTENSIONS Edited and extended by Giovanni Resta, Jan 16 2006 a(9)-a(10) from Giovanni Resta, Feb 23 2014 STATUS approved

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Last modified December 13 17:37 EST 2019. Contains 329970 sequences. (Running on oeis4.)