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 A110753 a(n) is the number of divisors of the concatenation of 2178 with itself n times. 3
 18, 72, 384, 288, 576, 3072, 1152, 9216, 7680, 9216, 6144, 24576, 2304, 18432, 3145728, 147456, 4608, 491520, 288, 147456, 9437184, 98304, 4608, 12582912, 589824, 36864, 1179648, 589824, 36864, 201326592 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS 2178 has the property that any number of concatenations of it with itself and its digit reversal have the same set of distinct prime factors. LINKS EXAMPLE a(2) = tau(21782178) = 72. MATHEMATICA k = 0; Do[k = (10^4 * k) + 2178; Print[DivisorSigma[0, k]], {n, 1, 30}] (* Ryan Propper, Aug 28 2005 *) Table[DivisorSigma[0, FromDigits[PadRight[{}, 4n, {2, 1, 7, 8}]]], {n, 30}] (* Harvey P. Dale, Jun 23 2014 *) CROSSREFS Cf. A110751, A110752. Sequence in context: A262000 A007276 A052619 * A154670 A041626 A039608 Adjacent sequences:  A110750 A110751 A110752 * A110754 A110755 A110756 KEYWORD base,nonn AUTHOR Amarnath Murthy, Aug 11 2005 EXTENSIONS More terms from Ryan Propper, Aug 28 2005 STATUS approved

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Last modified August 4 03:57 EDT 2021. Contains 346442 sequences. (Running on oeis4.)