|
|
A256539
|
|
Number of partitions of 4n into at most 5 parts.
|
|
2
|
|
|
1, 5, 18, 47, 101, 192, 333, 540, 831, 1226, 1747, 2418, 3266, 4319, 5608, 7166, 9027, 11229, 13811, 16814, 20282, 24260, 28796, 33940, 39744, 46262, 53550, 61667, 70673, 80631, 91606, 103664, 116875, 131310, 147042, 164147, 182702, 202787, 224484, 247877
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,2
|
|
LINKS
|
Index entries for linear recurrences with constant coefficients, signature (3,-3,2,-3,4,-4,3,-2,3,-3,1).
|
|
FORMULA
|
G.f.: -(x^7+4*x^6+5*x^5+7*x^4+6*x^3+6*x^2+2*x+1) / ((x-1)^5*(x^2+x+1)*(x^4+x^3+x^2+x+1)).
|
|
EXAMPLE
|
For n=2 the 18 partitions of 2*4 = 8 are [8], [1,7], [2,6], [3,5], [4,4], [1,1,6], [1,2,5], [1,3,4], [2,2,4], [2,3,3], [1,1,1,5], [1,1,2,4], [1,1,3,3], [1,2,2,3], [2,2,2,2], [1,1,1,1,4], [1,1,1,2,3] and [1,1,2,2,2].
|
|
PROG
|
(PARI) concat(1, vector(40, n, k=0; forpart(p=4*n, k++, , [1, 5]); k))
(PARI) Vec(-(x^7+4*x^6+5*x^5+7*x^4+6*x^3+6*x^2+2*x+1) / ((x-1)^5*(x^2+x+1)*(x^4+x^3+x^2+x+1)) + O(x^100))
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,easy
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|