|
| |
|
|
A080202
|
|
Triangle T(b,k) read by rows, giving numbers of pairs of unequal permutations of all the digits 1, ..., k in base b (k<b) whose ratio is an integer.
|
|
1
|
|
|
|
0, 0, 1, 0, 0, 1, 0, 0, 3, 25, 0, 0, 0, 2, 7, 0, 0, 0, 0, 68, 623, 0, 0, 0, 0, 0, 124, 1183, 0, 0, 0, 0, 0, 0, 2338, 24603, 0, 0, 0, 0, 0, 0, 3, 598, 5895, 0, 0, 0, 0, 0, 0, 0, 0, 161947, 2017603
(list;
table;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
3,9
|
|
|
COMMENTS
|
Terms computed by Michael Trott.
|
|
|
LINKS
|
Table of n, a(n) for n=3..57.
Eric Weisstein's World of Mathematics, Steffi Problem
|
|
|
EXAMPLE
|
Triangle is arranged as (b,k) = (3, 2), (4, 2), (4, 3), (5, 2), (5, 3), (5,4), (6,2), ....
In base 3, there are no solutions for 12, so T(3,2)=0. In base 4, there are no solutions for 12, so T(4,2)=0 and a single solution for 123, so T(4,3)=1. In base 5, there are no solutions with the digits 12 or 123, so T(5,1)=T(5,2)=0, but there is a single solution with the digits 1234: 4312_5/1234_5 = 3, so T(5,3)=1.
0;
0, 1;
0, 0, 1;
0, 0, 3, 25;
0, 0, 0, 2, 7;
0, 0, 0, 0, 68, 623;
0, 0, 0, 0, 0, 124, 1183;
|
|
|
CROSSREFS
|
T(b,b-1) gives A080203.
Sequence in context: A000856 A047678 A047938 * A085836 A073916 A076962
Adjacent sequences: A080199 A080200 A080201 * A080203 A080204 A080205
|
|
|
KEYWORD
|
nonn,tabl,base
|
|
|
AUTHOR
|
Eric W. Weisstein, Feb 05 2003
|
|
|
STATUS
|
approved
|
| |
|
|
