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A035626
Number of partitions of n into parts 4k+2 and 4k+3 with at least one part of each type.
4
0, 0, 0, 0, 1, 0, 1, 1, 3, 1, 4, 3, 7, 4, 10, 8, 15, 11, 21, 18, 30, 24, 42, 37, 56, 50, 78, 70, 102, 95, 137, 129, 179, 171, 236, 227, 303, 297, 395, 386, 502, 501, 643, 641, 814, 820, 1030, 1041, 1291, 1317, 1622, 1652, 2018, 2075, 2509, 2582, 3107, 3212, 3834
OFFSET
1,9
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..5000 (first 100 terms from Robert Price)
FORMULA
G.f.: (-1 + 1/Product_{k>=0} (1 - x^(4 k + 2)))*(-1 + 1/Product_{k>=0} (1 - x^(4 k + 3))). - Robert Price, Aug 16 2020
MATHEMATICA
nmax = 59; s1 = Range[0, nmax/4]*4 + 2; s2 = Range[0, nmax/4]*4 + 3;
Table[Count[IntegerPartitions[n, All, s1~Join~s2],
x_ /; ContainsAny[x, s1 ] && ContainsAny[x, s2 ]], {n, 1, nmax}] (* Robert Price, Aug 06 2020 *)
nmax = 59; l = Rest@CoefficientList[Series[(-1 + 1/Product[(1 - x^(4 k + 3)), {k, 0, nmax}])*(-1 + 1/Product[(1 - x^(4 k + 2)), {k, 0, nmax}]), {x, 0, nmax}], x] (* Robert Price, Aug 16 2020 *)
CROSSREFS
Bisection of A035695 (even part).
Sequence in context: A264596 A262214 A340760 * A082587 A364670 A060043
KEYWORD
nonn
STATUS
approved