|
Search: id:A046399
|
|
|
| A046399 |
|
Smallest squarefree palindrome with exactly n distinct prime factors. |
|
+0
2
|
|
| 1, 2, 6, 66, 858, 6006, 222222, 22444422, 244868442, 6434774346
(list; graph; listen)
|
|
|
OFFSET
|
0,2
|
|
|
COMMENT
|
Initial terms of sequences A046392-A046398.
|
|
REFERENCES
|
J.-P. Delahaye, Merveilleux nombres premiers ("Amazing primes"), p. 315, Pour la Science, Paris 2000.
|
|
EXAMPLE
|
a(4) = 2002 = 2*7*11*13.
|
|
MATHEMATICA
|
r[n_] := FromDigits[Reverse[IntegerDigits[n]]]; Do[k = 1; While[r[k] != k || !SquareFreeQ[k] || Length[Select[Divisors[k], PrimeQ]] != n, k++ ]; Print[k], {n, 0, 30}] - Ryan Propper (rpropper(AT)stanford.edu), Sep 16 2005
|
|
CROSSREFS
|
Cf. A046385.
Sequence in context: A066756 A070872 A055685 this_sequence A082619 A082617 A006517
Adjacent sequences: A046396 A046397 A046398 this_sequence A046400 A046401 A046402
|
|
KEYWORD
|
nonn,hard,base
|
|
AUTHOR
|
Patrick De Geest (pdg(AT)worldofnumbers.com), Jun 15 1998.
|
|
EXTENSIONS
|
Edited by N. J. A. Sloane (njas(AT)research.att.com), Dec 06 2008 at the suggestion of R. J. Mathar
|
|
|
Search completed in 0.002 seconds
|
