login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A370320 Number of non-condensed integer partitions of n, or partitions where it is not possible to choose a different divisor of each part. 25

%I #16 May 24 2024 03:49:57

%S 0,0,1,1,2,4,6,9,13,20,28,40,54,74,102,135,180,235,310,397,516,658,

%T 843,1066,1349,1687,2119,2634,3273,4045,4995,6128,7517,9171,11181,

%U 13579,16457,19884,23992,28859,34646,41506,49634,59211,70533,83836,99504,117867

%N Number of non-condensed integer partitions of n, or partitions where it is not possible to choose a different divisor of each part.

%C Includes all partitions containing 1.

%e The a(0) = 0 through a(8) = 13 partitions:

%e . . (11) (111) (211) (221) (222) (331) (611)

%e (1111) (311) (411) (511) (2222)

%e (2111) (2211) (2221) (3221)

%e (11111) (3111) (3211) (3311)

%e (21111) (4111) (4211)

%e (111111) (22111) (5111)

%e (31111) (22211)

%e (211111) (32111)

%e (1111111) (41111)

%e (221111)

%e (311111)

%e (2111111)

%e (11111111)

%t Table[Length[Select[IntegerPartitions[n], Length[Select[Tuples[Divisors/@#], UnsameQ@@#&]]==0&]],{n,0,30}]

%Y The complement is counted by A239312 (condensed partitions).

%Y These partitions have ranks A355740.

%Y Factorizations in the case of prime factors are A368413, complement A368414.

%Y The complement for prime factors is A370592, ranks A368100.

%Y The version for prime factors (not all divisors) is A370593, ranks A355529.

%Y For a unique choice we have A370595, ranks A370810.

%Y For multiple choices we have A370803, ranks A370811.

%Y The case without ones is A370804, complement A370805.

%Y The version for factorizations is A370813, complement A370814.

%Y A000005 counts divisors.

%Y A000041 counts integer partitions.

%Y A027746 lists prime factors, A112798 indices, length A001222.

%Y A355731 counts choices of a divisor of each prime index, firsts A355732.

%Y A355741 chooses prime factors of prime indices, variations A355744, A355745.

%Y Cf. A355535, A355739, A367867, A368097, A368110, A370583, A370584, A370594, A370806, A370807, A370808.

%K nonn

%O 0,5

%A _Gus Wiseman_, Mar 02 2024

%E a(31)-a(47) from _Alois P. Heinz_, Mar 03 2024

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified July 12 15:19 EDT 2024. Contains 374251 sequences. (Running on oeis4.)