|
| |
|
|
A110752
|
|
a(n) = Tau(N), where N = the number obtained as a concatenation of 1089 with itself n times. Tau(n) = number of divisors of n.
|
|
3
| |
|
|
9, 36, 192, 144, 288, 1536, 576, 4608, 3840, 4608, 3072, 12288, 1152, 9216, 1572864, 73728, 2304, 245760, 144, 73728, 4718592, 49152, 2304, 6291456, 294912, 18432, 589824, 294912, 18432, 100663296
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
COMMENTS
| 1089 has the property that any number of concatenation of it with self and the digit reversal have same prime divisors.
|
|
|
EXAMPLE
| a(2) =tau(10891089) = 36.
|
|
|
MATHEMATICA
| k = 0; Do[k = 10^4 * k + 1089; Print[DivisorSigma[0, k]], {n, 1, 30}] (Propper)
|
|
|
CROSSREFS
| Cf. A110751, A110753.
Sequence in context: A034557 A002063 A075674 * A094973 A038780 A073984
Adjacent sequences: A110749 A110750 A110751 * A110753 A110754 A110755
|
|
|
KEYWORD
| base,nonn
|
|
|
AUTHOR
| Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Aug 11 2005
|
|
|
EXTENSIONS
| More terms from Ryan Propper (rpropper(AT)stanford.edu), Oct 15 2005
|
| |
|
|
