cp's OEIS Frontend

A342230 Total number of parts which are powers of 2 in all partitions of n.

%I A342230 #6 Mar 07 2021 03:56:09
%S A342230 0,1,3,5,11,17,29,44,71,102,153,216,311,429,599,810,1108,1475,1974,
%T A342230 2595,3421,4441,5776,7422,9542,12147,15459,19513,24617,30838,38590,
%U A342230 48012,59662,73754,91056,111916,137357,167922,204982,249349,302873,366732,443390,534573
%N A342230 Total number of parts which are powers of 2 in all partitions of n.
%F A342230 G.f.: Sum_{k>=0} x^(2^k)/(1 - x^(2^k)) / Product_{j>=1} (1 - x^j).
%F A342230 a(n) = Sum_{k=1..n} A001511(k) * A000041(n-k).
%F A342230 a(n) = A000070(n-1) + A073119(n).
%e A342230 For n = 4 we have:
%e A342230 ------------------------------------
%e A342230 Partitions        Number of parts
%e A342230 .              which are powers of 2
%e A342230 ------------------------------------
%e A342230 4 ..................... 1
%e A342230 3 + 1 ................. 1
%e A342230 2 + 2 ................. 2
%e A342230 2 + 1 + 1 ............. 3
%e A342230 1 + 1 + 1 + 1 ......... 4
%e A342230 ------------------------------------
%e A342230 Total ................ 11
%e A342230 So a(4) = 11.
%t A342230 nmax = 43; CoefficientList[Series[Sum[x^(2^k)/(1 - x^(2^k)), {k, 0, Floor[Log[2, nmax]] + 1}]/Product[(1 - x^j), {j, 1, nmax}], {x, 0, nmax}], x]
%t A342230 Table[Sum[IntegerExponent[2 k, 2] PartitionsP[n - k], {k, 1, n}], {n, 0, 43}]
%Y A342230 Cf. A000041, A000070, A000079, A001511, A006128, A073119, A342231.
%K A342230 nonn
%O A342230 0,3
%A A342230 _Ilya Gutkovskiy_, Mar 06 2021