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This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A358828 Number of twice-partitions of n with no singletons.

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%I A358828 #5 Dec 03 2022 13:54:02
%S A358828 1,0,1,2,5,8,19,30,68,111,229,380,799,1280,2519,4325,8128,13666,25758,
%T A358828 43085,79300,134571,240124,407794,730398,1224821,2152122,3646566,
%U A358828 6338691,10657427,18469865,30913539,53108364,88953395,151396452,253098400,429416589
%N A358828 Number of twice-partitions of n with no singletons.
%C A358828 A twice-partition of n is a sequence of integer partitions, one of each part of an integer partition of n.
%F A358828 G.f.: Product_{k>=1} 1/(1-(A000041(k)-1)*x^k).
%e A358828 The a(2) = 1 through a(6) = 19 twice-partitions:
%e A358828   (11)  (21)   (22)      (32)       (33)
%e A358828         (111)  (31)      (41)       (42)
%e A358828                (211)     (221)      (51)
%e A358828                (1111)    (311)      (222)
%e A358828                (11)(11)  (2111)     (321)
%e A358828                          (11111)    (411)
%e A358828                          (21)(11)   (2211)
%e A358828                          (111)(11)  (3111)
%e A358828                                     (21111)
%e A358828                                     (111111)
%e A358828                                     (21)(21)
%e A358828                                     (22)(11)
%e A358828                                     (31)(11)
%e A358828                                     (111)(21)
%e A358828                                     (21)(111)
%e A358828                                     (211)(11)
%e A358828                                     (111)(111)
%e A358828                                     (1111)(11)
%e A358828                                     (11)(11)(11)
%t A358828 twiptn[n_]:=Join@@Table[Tuples[IntegerPartitions/@ptn],{ptn,IntegerPartitions[n]}];
%t A358828 Table[Length[Select[twiptn[n],FreeQ[Length/@#,1]&]],{n,0,10}]
%Y A358828 The version for multiset partitions of integer partitions is A304966.
%Y A358828 Allowing singletons other than (1) gives A358829.
%Y A358828 A002865 counts partitions with no 1's.
%Y A358828 A063834 counts twice-partitions, strict A296122, row-sums of A321449.
%Y A358828 Cf. A000009, A000041, A000219, A001970, A072233, A358824.
%K A358828 nonn
%O A358828 0,4
%A A358828 _Gus Wiseman_, Dec 03 2022