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A322968 Number of integer partitions of n with no ones whose parts are all powers of the same squarefree number. 1

%I #5 Jan 02 2019 03:48:21

%S 1,0,1,1,2,1,4,1,4,2,6,1,9,1,8,4,10,1,14,1,16,5,16,1,24,2,22,5,28,1,

%T 37,1,36,7,38,4,55,1,48,9,63,1,73,1,76,12,76,1,105,2,98,11,116,1,128,

%U 5,143,14,142,1,186,1,168,18,202,5

%N Number of integer partitions of n with no ones whose parts are all powers of the same squarefree number.

%C First differs from A072721 at a(12) = 9, A072721(12) = 10.

%e The a(2) = 1 through a(12) = 9 integer partitions (A = 10, B = 11):

%e (2) (3) (4) (5) (6) (7) (8) (9) (A) (B) (66)

%e (22) (33) (44) (333) (55) (84)

%e (42) (422) (82) (93)

%e (222) (2222) (442) (444)

%e (4222) (822)

%e (22222) (3333)

%e (4422)

%e (42222)

%e (222222)

%e The a(20) = 16 integer partitions:

%e (10,10), (16,4),

%e (8,8,4), (16,2,2),

%e (5,5,5,5), (8,4,4,4), (8,8,2,2),

%e (4,4,4,4,4), (8,4,4,2,2),

%e (4,4,4,4,2,2), (8,4,2,2,2,2),

%e (4,4,4,2,2,2,2), (8,2,2,2,2,2,2),

%e (4,4,2,2,2,2,2,2),

%e (4,2,2,2,2,2,2,2,2),

%e (2,2,2,2,2,2,2,2,2,2).

%t radbase[n_]:=n^(1/GCD@@FactorInteger[n][[All,2]]);

%t powsqfQ[n_]:=SameQ@@Last/@FactorInteger[n];

%t Table[Length[Select[IntegerPartitions[n],And[FreeQ[#,1],And@@powsqfQ/@#,SameQ@@radbase/@#]&]],{n,30}]

%Y Cf. A001597, A005117, A018819, A023893, A052410, A072720, A072721, A072774, A102430, A322900, A322903, A322911, A322912.

%K nonn

%O 0,5

%A _Gus Wiseman_, Jan 01 2019

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Last modified July 19 02:27 EDT 2024. Contains 374388 sequences. (Running on oeis4.)