|
Search: id:A110753
|
|
|
| A110753 |
|
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. |
|
+0
4
|
|
| 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; listen)
|
|
|
OFFSET
|
1,1
|
|
|
COMMENT
|
2178 has the property that any number of concatenation of it with self and the digit reversal have same prime divisors.
|
|
EXAMPLE
|
a(2) =tau(21782178) = 72.
|
|
MATHEMATICA
|
k = 0; Do[k = (10^4 * k) + 2178; Print[DivisorSigma[0, k]], {n, 1, 30}] (Propper)
|
|
CROSSREFS
|
Cf. A110751, A110752.
Sequence in context: A069058 A007276 A052619 this_sequence A154670 A041626 A039608
Adjacent sequences: A110750 A110751 A110752 this_sequence A110754 A110755 A110756
|
|
KEYWORD
|
base,nonn
|
|
AUTHOR
|
Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Aug 11 2005
|
|
EXTENSIONS
|
More terms from Ryan Propper (rpropper(AT)stanford.edu), Aug 28 2005
|
|
|
Search completed in 0.002 seconds
|
