|
|
A035660
|
|
Number of partitions of n into parts 7k+1 and 7k+5 with at least one part of each type.
|
|
3
|
|
|
0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 2, 2, 4, 4, 4, 5, 5, 7, 7, 10, 12, 12, 14, 14, 18, 20, 24, 28, 29, 33, 35, 41, 45, 51, 59, 63, 71, 75, 85, 94, 104, 118, 126, 140, 150, 166, 182, 198, 222, 239, 263, 282, 308, 337, 364, 403, 433, 473, 508, 550, 599, 643, 705, 758, 823, 884
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,11
|
|
LINKS
|
|
|
FORMULA
|
G.f.: (-1 + 1/Product_{k>=0} (1 - x^(7 k + 1)))*(-1 + 1/Product_{k>=0} (1 - x^(7 k + 5))). - Robert Price, Aug 16 2020
|
|
MATHEMATICA
|
nmax = 66; s1 = Range[0, nmax/7]*7 + 1; s2 = Range[0, nmax/7]*7 + 5;
Table[Count[IntegerPartitions[n, All, s1~Join~s2],
x_ /; ContainsAny[x, s1 ] && ContainsAny[x, s2 ]], {n, 1, nmax}] (* Robert Price, Aug 14 2020 *)
nmax = 66; l = Rest@CoefficientList[Series[(-1 + 1/Product[(1 - x^(7 k + 1)), {k, 0, nmax}])*(-1 + 1/Product[(1 - x^(7 k + 5)), {k, 0, nmax}]), {x, 0, nmax}], x] (* Robert Price, Aug 16 2020 *)
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|