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Expansion of Product_{k>=1} (1 - q(k)*x^k), where q(k) = number of partitions of k into distinct parts (A000009).
4

%I #4 May 18 2018 19:48:38

%S 1,-1,-1,-1,0,1,-1,4,2,3,1,8,-8,10,-8,-9,-15,-6,-46,-14,-65,-28,14,

%T -29,-43,-37,298,59,234,165,738,354,1083,703,1944,-2024,1917,-1085,

%U 3658,-2385,-6421,-7220,118,-15569,-11604,-19162,-9448,-36140,-24561,-50505,-24807,47645

%N Expansion of Product_{k>=1} (1 - q(k)*x^k), where q(k) = number of partitions of k into distinct parts (A000009).

%C Convolution inverse of A270995.

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/PartitionFunctionQ.html">Partition Function Q</a>

%H <a href="/index/Par#part">Index entries for sequences related to partitions</a>

%F G.f.: Product_{k>=1} (1 - A000009(k)*x^k).

%t nmax = 51; CoefficientList[Series[Product[(1 - PartitionsQ[k] x^k), {k, 1, nmax}], {x, 0, nmax}], x]

%t a[n_] := a[n] = If[n == 0, 1, Sum[-Sum[d PartitionsQ[d]^(k/d), {d, Divisors[k]}] a[n - k], {k, 1, n}]/n]; Table[a[n], {n, 0, 51}]

%Y Cf. A000009, A270995, A271619, A304783, A304785.

%K sign

%O 0,8

%A _Ilya Gutkovskiy_, May 18 2018