|
|
A112422
|
|
Number of 6-element subsets of {1,2,3,...,n} for which the sum-set has 13 elements.
|
|
1
|
|
|
3, 11, 19, 27, 35, 43, 54, 65, 81, 97, 113, 129, 148, 167, 186, 210, 234, 258, 285, 312, 339, 366, 398, 430, 465, 500, 535, 570, 605, 645, 688, 731, 774, 817, 860, 903, 954, 1005, 1056, 1107, 1158, 1209, 1263, 1322, 1381, 1440, 1499, 1558, 1620, 1682, 1749
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
7,1
|
|
LINKS
|
Index entries for linear recurrences with constant coefficients, signature (1,0,0,0,0,1,0,-1,0,0,0,0,-1,1).
|
|
FORMULA
|
G.f.: x^7*(3 +8*x +8*x^2 +8*x^3 +8*x^4 +8*x^5 +8*x^6) / ((1 -x)^3*(1 +x)*(1 -x +x^2)*(1 +x +x^2)*(1 +x +x^2 +x^3 +x^4 +x^5 +x^6)). - Corrected by Colin Barker, Jan 10 2017
|
|
MATHEMATICA
|
LinearRecurrence[{1, 0, 0, 0, 0, 1, 0, -1, 0, 0, 0, 0, -1, 1}, {3, 11, 19, 27, 35, 43, 54, 65, 81, 97, 113, 129, 148, 167}, 60] (* Harvey P. Dale, Jul 01 2020 *)
|
|
PROG
|
(PARI) Vec(x^7*(3 +8*x +8*x^2 +8*x^3 +8*x^4 +8*x^5 +8*x^6) / ((1 -x)^3*(1 +x)*(1 -x +x^2)*(1 +x +x^2)*(1 +x +x^2 +x^3 +x^4 +x^5 +x^6)) + O(x^60)) \\ Colin Barker, Jan 10 2017
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,easy
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|