|
|
A017054
|
|
a(n) = (7*n + 6)^2.
|
|
1
|
|
|
36, 169, 400, 729, 1156, 1681, 2304, 3025, 3844, 4761, 5776, 6889, 8100, 9409, 10816, 12321, 13924, 15625, 17424, 19321, 21316, 23409, 25600, 27889, 30276, 32761, 35344, 38025, 40804, 43681, 46656
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,1
|
|
COMMENTS
|
If Y is a fixed 2-subset of a (7n+1)-set X then a(n-1) is the number of 3-subsets of X intersecting Y. - Milan Janjic, Oct 21 2007
|
|
LINKS
|
|
|
FORMULA
|
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3); a(0)=36, a(1)=169, a(2)=400. - Harvey P. Dale, Apr 28 2016
|
|
MATHEMATICA
|
(7*Range[0, 30]+6)^2 (* or *) LinearRecurrence[{3, -3, 1}, {36, 169, 400}, 40] (* Harvey P. Dale, Apr 28 2016 *)
|
|
PROG
|
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,easy
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|