|
Search: id:A067106
|
|
|
| A067106 |
|
a(n) = smallest number whose digit product equals n!/m where m is the product of all prime factors > 7 of n! (with multiplicity). |
|
+0
1
|
|
| 1, 2, 6, 38, 358, 2589, 25789, 257889, 2578899, 45578899, 45578899, 556788899, 556788899, 25567788899, 455577888999, 5557788888999, 5557788888999, 255577888889999, 255577888889999, 5555778888889999, 355557778888889999
(list; graph; listen)
|
|
|
OFFSET
|
1,2
|
|
|
EXAMPLE
|
For n = 12 we have n! = 479001600, m = 11 and n!/m = 43545600 = 5*5*6*7*8*8*8*9*9, so a(12) = 556788899.
|
|
PROGRAM
|
(PARI) {for(n=1, 21, f=factor(n!); m=1; for(j=1, matsize(f)[1], if(f[j, 1]<=7, m=m*f[j, 1]^f[j, 2])); s=if(m>1, "", "1"); k=9; while(m>1, d=divrem(m, k); if(d[2]==0, s=concat(k, s); m=d[1], k--)); print1(eval(s), ", "))}
|
|
CROSSREFS
|
Sequence in context: A078673 A052841 A068184 this_sequence A032111 A013703 A002031
Adjacent sequences: A067103 A067104 A067105 this_sequence A067107 A067108 A067109
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Jan 07 2002
|
|
EXTENSIONS
|
Edited, corrected and extended by Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Jun 17 2003
|
|
|
Search completed in 0.002 seconds
|
