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A371284 Number of integer partitions of n whose distinct parts form the set of divisors of some number.

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%I A371284 #5 Mar 22 2024 09:16:47
%S A371284 0,1,1,2,3,4,5,8,9,11,12,16,18,23,25,32,36,42,47,57,62,73,81,96,106,
%T A371284 123,132,154,168,190,207,240,259,293,317,359,388,434,469,529,574,635,
%U A371284 688,768,826,915,987,1093,1181,1302,1397,1540,1662,1818,1959,2149,2309
%N A371284 Number of integer partitions of n whose distinct parts form the set of divisors of some number.
%C A371284 The Heinz numbers of these partitions are given by A371288.
%e A371284 The partition y = (10,5,5,5,2,2,1) has distinct parts {1,2,5,10}, which form the set of divisors of 10, so y is counted under a(30).
%e A371284 The a(1) = 1 through a(8) = 9 partitions:
%e A371284   (1)  (11)  (21)   (31)    (221)    (51)      (331)      (71)
%e A371284              (111)  (211)   (311)    (2211)    (421)      (3311)
%e A371284                     (1111)  (2111)   (3111)    (511)      (4211)
%e A371284                             (11111)  (21111)   (2221)     (5111)
%e A371284                                      (111111)  (22111)    (22211)
%e A371284                                                (31111)    (221111)
%e A371284                                                (211111)   (311111)
%e A371284                                                (1111111)  (2111111)
%e A371284                                                           (11111111)
%t A371284 Table[Length[Select[IntegerPartitions[n], Union[#]==Divisors[Max[#]]&]],{n,0,30}]
%Y A371284 The strict case is A054973, ranks A371283 (unsorted version A275700).
%Y A371284 These partitions have ranks A371288.
%Y A371284 A000005 counts divisors, row-lengths of A027750.
%Y A371284 A000041 counts integer partitions, strict A000009.
%Y A371284 A008284 counts partitions by length, strict A008289.
%Y A371284 Cf. A001221, A002865, A239312, A370803, A371172, A371286, A371285.
%K A371284 nonn
%O A371284 0,4
%A A371284 _Gus Wiseman_, Mar 22 2024