OFFSET
1,3
COMMENTS
LINKS
FORMULA
EXAMPLE
For n = 5 and k = 2 we have that the 4th shell of 5 contains two regions: [2] and [4,2,1,1,1]. Then we can see that the 5th shell of 5 contains two regions: [3] and [5,2,1,1,1,1,1]. Therefore the total number of regions in the last two shells of 5 is T(5,2) = 2+2 = 4 (see illustration in the link section).
Triangle begins:
1;
1, 2;
1, 2, 3;
2, 3, 4, 5;
2, 4, 5, 6, 7;
4, 6, 8, 9, 10, 11;
4, 8, 10, 12, 13, 14, 15;
7, 11, 15, 17, 19, 20, 21, 22;
8, 15, 19, 23, 25, 27, 28, 29, 30;
12, 20, 27, 31, 35, 37, 39, 40, 41, 42;
14, 26, 34, 41, 45, 49, 51, 53, 54, 55, 56;
21, 35, 47, 55, 62, 66, 70, 72, 74, 75, 76, 77;
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Omar E. Pol, Apr 27 2012
STATUS
approved