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A371446
Number of carry-connected integer partitions whose distinct parts have no binary containments.
5
1, 1, 2, 2, 3, 2, 4, 2, 5, 4, 4, 4, 8, 4, 7, 7, 12, 10, 14, 12, 15, 19, 19, 21, 32, 27, 33, 40, 46, 47, 61, 52, 75, 89, 95, 104, 129, 129, 149, 176, 188, 208, 249, 257, 296, 341, 373, 394, 476, 496, 552
OFFSET
0,3
COMMENTS
These partitions are ranked by A371445.
A binary index of n is any position of a 1 in its reversed binary expansion. The binary indices of n are row n of A048793.
A binary carry of two positive integers is an overlap of binary indices. An integer partition is binary carry-connected iff the graph with one vertex for each part and edges corresponding to binary carries is connected.
A binary containment is a containment of binary indices. For example, the numbers {3,5} have binary indices {{1,2},{1,3}}, so there is a binary carry but not a binary containment.
EXAMPLE
The a(12) = 8 through a(14) = 7 partitions:
(12) (13) (14)
(6,6) (10,3) (7,7)
(9,3) (5,5,3) (9,5)
(4,4,4) (1,1,1,1,1,1,1,1,1,1,1,1,1) (6,5,3)
(6,3,3) (5,3,3,3)
(3,3,3,3) (2,2,2,2,2,2,2)
(2,2,2,2,2,2) (1,1,1,1,1,1,1,1,1,1,1,1,1,1)
(1,1,1,1,1,1,1,1,1,1,1,1)
MATHEMATICA
stableQ[u_, Q_]:=!Apply[Or, Outer[#1=!=#2&&Q[#1, #2]&, u, u, 1], {0, 1}];
bix[n_]:=Join@@Position[Reverse[IntegerDigits[n, 2]], 1];
prix[n_]:=If[n==1, {}, Flatten[Cases[FactorInteger[n], {p_, k_}:>Table[PrimePi[p], {k}]]]];
csm[s_]:=With[{c=Select[Subsets[Range[Length[s]], {2}], Length[Intersection@@s[[#]]]>0&]}, If[c=={}, s, csm[Sort[Append[Delete[s, List/@c[[1]]], Union@@s[[c[[1]]]]]]]]];
Table[Length[Select[IntegerPartitions[n], stableQ[bix/@Union[#], SubsetQ]&&Length[csm[bix/@#]]<=1&]], {n, 0, 30}]
CROSSREFS
The first condition (carry-connected) is A325098.
The second condition (stable) is A325109.
Ranks for binary indices of binary indices are A326750 = A326704 /\ A326749.
Ranks for prime indices of prime indices are A329559 = A305078 /\ A316476.
Ranks for prime indices of binary indices are A371294 = A087086 /\ A371291.
Ranks for binary indices of prime indices are A371445 = A325118 /\ A371455.
A001187 counts connected graphs.
A007718 counts non-isomorphic connected multiset partitions.
A048143 counts connected antichains of sets.
A048793 lists binary indices, reverse A272020, length A000120, sum A029931.
A070939 gives length of binary expansion.
A326964 counts connected set-systems, covering A323818.
Sequence in context: A305975 A304751 A117658 * A325564 A323888 A289435
KEYWORD
nonn,more
AUTHOR
Gus Wiseman, Apr 02 2024
STATUS
approved