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A110753
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a(n) = Tau(N), where N = the number obtained as a concatenation of 2178 with itself n times. Tau(n) = number of divisors of n.
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3
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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; internal format)
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OFFSET
| 1,1
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COMMENTS
| 2178 has the property that any number of concatenation of it with self and the digit reversal have same prime divisors.
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EXAMPLE
| a(2) =tau(21782178) = 72.
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MATHEMATICA
| k = 0; Do[k = (10^4 * k) + 2178; Print[DivisorSigma[0, k]], {n, 1, 30}] (Propper)
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CROSSREFS
| Cf. A110751, A110752.
Sequence in context: A069058 A007276 A052619 * A174085 A154670 A041626
Adjacent sequences: A110750 A110751 A110752 * A110754 A110755 A110756
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KEYWORD
| base,nonn
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AUTHOR
| Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Aug 11 2005
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EXTENSIONS
| More terms from Ryan Propper (rpropper(AT)stanford.edu), Aug 28 2005
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