OFFSET
1,2
COMMENTS
T(n,k) is the number of k-digit numbers in base n+1 with distinct positive digits that form an integer interval when sorted.
T(9,k) is also the number of numbers with k digits in A288528.
FORMULA
EXAMPLE
Triangle begins:
1;
2, 2;
3, 4, 6;
4, 6, 12, 24;
5, 8, 18, 48, 120;
6, 10, 24, 72, 240, 720;
7, 12, 30, 96, 360, 1440, 5040;
8, 14, 36, 120, 480, 2160, 10080, 40320;
9, 16, 42, 144, 600, 2880, 15120, 80640, 362880;
10, 18, 48, 168, 720, 3600, 20160, 120960, 725760, 3628800;
11, 20, 54, 192, 840, 4320, 25200, 161280, 1088640, 7257600, 39916800;
...
For n = 9 and k = 2: T(9,2) is the number of numbers with two digits in A288528.
MATHEMATICA
Table[(n - k + 1) k!, {n, 11}, {k, n}] // Flatten (* Michael De Vlieger, Jun 15 2017 *)
CROSSREFS
KEYWORD
AUTHOR
Omar E. Pol, Jun 15 2017
STATUS
approved