A305563 -id:A305563 - cp's OEIS frontend

A305567 Irregular triangle where T(n,k) is the number of finite sets of positive integers with least common multiple n and greatest common divisor k, where k runs over all divisors of n.

1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 7, 1, 1, 1, 1, 1, 4, 2, 1, 1, 2, 1, 1, 7, 1, 1, 1, 1, 1, 32, 7, 2, 1, 1, 1, 1, 1, 7, 1, 1, 1, 7, 1, 1, 1, 8, 4, 2, 1, 1, 1, 1, 32, 2, 7, 1, 1, 1, 1, 1, 32, 7, 1, 2, 1, 1, 7, 1, 1, 1, 7, 1, 1, 1, 1, 1, 136, 32, 4, 7, 2, 1, 1, 1, 2

Offset: 1

Gus Wiseman, Jun 05 2018

			Triangle begins:
   1
   1  1
   1  1
   2  1  1
   1  1
   7  1  1  1
   1  1
   4  2  1  1
   2  1  1
   7  1  1  1
   1  1
  32  7  2  1  1  1
   1  1
   7  1  1  1
   7  1  1  1
   8  4  2  1  1
   1  1
  32  2  7  1  1  1
   1  1
  32  7  1  2  1  1

Row lengths are A000005.

Cf. A076078, A181819, A281116, A285572, A290103, A304818, A305563, A305564, A305565, A305566.

Table[Length[Select[Subsets[Divisors[n]],And[GCD@@#==k,LCM@@#==n]&]],{n,30},{k,Divisors[n]}]

A305735 Number of integer partitions of n whose greatest common divisor is a prime number.

Original entry on oeis.org

0, 1, 1, 1, 1, 3, 1, 3, 2, 7, 1, 10, 1, 15, 8, 17, 1, 34, 1, 37, 16, 56, 1, 80, 6, 101, 27, 122, 1, 208, 1, 209, 57, 297, 20, 410, 1, 490, 102, 599, 1, 901, 1, 948, 194, 1255, 1, 1690, 14, 1985, 298, 2337, 1, 3327, 61, 3597, 491, 4565, 1, 6031, 1, 6842, 802

Offset: 1

Gus Wiseman, Jun 22 2018

nonn

			The a(10) = 7 integer partitions are (82), (64), (622), (55), (442), (4222), (22222).

Andrew Howroyd, Table of n, a(n) for n = 1..1000

Cf. A000040, A000041, A000837, A018783, A100953, A143519, A289508, A302698, A305563, A305731.

Table[Length[Select[IntegerPartitions[n],PrimeQ[GCD@@#]&]],{n,20}]

seq(n)={dirmul(vector(n, n, numbpart(n)), dirmul(vector(n, n, moebius(n)), vector(n, n, isprime(n))))} \\ Andrew Howroyd, Jun 22 2018

a(n) = Sum_{d|n} A143519(d) * A000041(n/d). - Andrew Howroyd, Jun 22 2018

A319179 Number of integer partitions of n that are relatively prime but not aperiodic. Number of integer partitions of n that are aperiodic but not relatively prime.

Original entry on oeis.org

0, 1, 1, 1, 1, 2, 1, 3, 2, 6, 1, 9, 1, 14, 7, 17, 1, 32, 1, 36, 15, 55, 1, 77, 6, 100, 27, 121, 1, 200, 1, 209, 56, 296, 19, 403, 1, 489, 101, 596, 1, 885, 1, 947, 192, 1254, 1, 1673, 14, 1979, 297, 2336, 1, 3300, 60, 3594, 490, 4564, 1, 5988, 1, 6841, 800

Offset: 1

Gus Wiseman, Sep 12 2018

nonn

An integer partition is aperiodic if its multiplicities are relatively prime.

			The a(12) = 9 integer partitions that are relatively prime but not aperiodic:
  (5511),
  (332211), (333111), (441111),
  (22221111), (33111111),
  (222111111),
  (2211111111),
  (111111111111).
The a(12) = 9 integer partitions that are aperiodic but not relatively prime:
  (12),
  (8,4), (9,3), (10,2),
  (6,3,3), (6,4,2), (8,2,2),
  (6,2,2,2),
  (4,2,2,2,2).

Cf. A000837, A018783, A047966, A100953, A305563, A319149, A319160, A319162, A319164.

Table[Length[Select[IntegerPartitions[n],And[GCD@@#==1,GCD@@Length/@Split[#]>1]&]],{n,30}]

A319299 Irregular triangle where T(n,k) is the number of integer partitions of n with GCD equal to the k-th divisor of n.

Original entry on oeis.org

1, 1, 1, 2, 1, 3, 1, 1, 6, 1, 7, 2, 1, 1, 14, 1, 17, 3, 1, 1, 27, 2, 1, 34, 6, 1, 1, 55, 1, 63, 7, 3, 2, 1, 1, 100, 1, 119, 14, 1, 1, 167, 6, 2, 1, 209, 17, 3, 1, 1, 296, 1, 347, 27, 7, 2, 1, 1, 489, 1, 582, 34, 6, 3, 1, 1, 775, 14, 2, 1, 945, 55, 1, 1, 1254

Offset: 1

Gus Wiseman, Sep 16 2018

			Triangle begins:
    1
    1   1
    2   1
    3   1   1
    6   1
    7   2   1   1
   14   1
   17   3   1   1
   27   2   1
   34   6   1   1
   55   1
   63   7   3   2   1   1
  100   1
  119  14   1   1
  167   6   2   1
  209  17   3   1   1
  296   1
  347  27   7   2   1   1
  489   1
  582  34   6   3   1   1

Robert Israel, Table of n, a(n) for n = 1..10006 (rows 1 to 1358, flattened)

A regular version is A168532. Row lengths are A000005. Row sums are A000041. First column is A000837.

Cf. A018783, A027750, A078374, A078392, A289508, A289509, A303139, A305563, A319300.

# with table A000837 obtained from that sequence
f:= proc(n) local D,d;
  D:= sort(convert(numtheory:-divisors(n),list),`>`);
  seq(A000837[d],d=D)
end proc:
map(f, [$1..60]); # Robert Israel, Jul 09 2020

Table[Length[Select[IntegerPartitions[n],GCD@@#==k&]],{n,20},{k,Divisors[n]}]

T(n,k) = A000837(n/A027750(n,k)).

A325332 Number of totally abnormal integer partitions of n.

Original entry on oeis.org

0, 0, 1, 1, 2, 1, 3, 1, 4, 2, 5, 1, 8, 1, 7, 5, 10, 2, 16, 4, 21, 15, 24, 17, 49, 29, 53, 53, 84, 65, 121, 92, 148, 141, 186, 179, 280, 223, 317, 318, 428, 387, 576, 512, 700, 734, 899, 900, 1260, 1207, 1551, 1668, 2041, 2109, 2748, 2795, 3463, 3775, 4446

Offset: 0

Gus Wiseman, May 01 2019

nonn

A multiset is normal if its union is an initial interval of positive integers. A multiset is totally abnormal if it is not normal and either it is a singleton or its multiplicities form a totally abnormal multiset.

The Heinz numbers of these partitions are given by A325372.

			The a(2) = 1 through a(12) = 8 totally abnormal partitions (A = 10, B = 11, C = 12):
  (2)  (3)  (4)   (5)  (6)    (7)  (8)     (9)    (A)      (B)   (C)
            (22)       (33)        (44)    (333)  (55)           (66)
                       (222)       (2222)         (3322)         (444)
                                   (3311)         (4411)         (3333)
                                                  (22222)        (4422)
                                                                 (5511)
                                                                 (222222)
                                                                 (333111)

Cf. A181819, A275870, A305563, A317088, A317245, A317491, A317589, A319149, A319810, A325372.

normQ[m_]:=Or[m=={},Union[m]==Range[Max[m]]];
antinrmQ[ptn_]:=!normQ[ptn]&&(Length[ptn]==1||antinrmQ[Sort[Length/@Split[ptn]]]);
Table[Length[Select[IntegerPartitions[n],antinrmQ]],{n,0,30}]

A305736 Number of integer partitions of n whose greatest common divisor is composite (nonprime and > 1).

Original entry on oeis.org

0, 0, 0, 1, 0, 1, 0, 2, 1, 1, 0, 4, 0, 1, 1, 5, 0, 4, 0, 8, 1, 1, 0, 14, 1, 1, 3, 16, 0, 10, 0, 22, 1, 1, 1, 41, 0, 1, 1, 45, 0, 18, 0, 57, 9, 1, 0, 94, 1, 8, 1, 102, 0, 38, 1, 138, 1, 1, 0, 221, 0, 1, 17, 231, 1, 59, 0, 298, 1, 22

Offset: 1

Gus Wiseman, Jun 22 2018

nonn

			The a(12) = 4 integer partitions are (12), (8 4), (6 6), (4 4 4).

Andrew Howroyd, Table of n, a(n) for n = 1..1000

Cf. A000040, A000837, A018783, A100953, A289508, A302698, A305563, A305731, A305735.

Table[Length[Select[IntegerPartitions[n],!(GCD@@#==1||PrimeQ[GCD@@#])&]],{n,0,20}]

seq(n)={dirmul(vector(n, n, numbpart(n)), dirmul(vector(n, n, moebius(n)), vector(n, n, n>1&&!isprime(n))))} \\ Andrew Howroyd, Jun 22 2018

a(n) = A018783(n) - A305735(n). - Andrew Howroyd, Jun 22 2018

A319811 Number of totally aperiodic integer partitions of n.

Original entry on oeis.org

1, 1, 2, 3, 6, 7, 14, 17, 27, 34, 55, 63, 99, 117, 162, 203, 286, 333, 469, 558, 737, 903, 1196, 1414, 1860, 2232, 2839, 3422, 4359, 5144, 6531, 7762, 9617, 11479, 14182, 16715, 20630, 24333, 29569, 34890, 42335, 49515, 59871, 70042, 83810, 98105, 117152

Offset: 1

Gus Wiseman, Sep 28 2018

nonn

An integer partition is totally aperiodic iff either it is strict or it is aperiodic with totally aperiodic multiplicities.

			The a(6) = 7 aperiodic integer partitions are: (6), (51), (42), (411), (321), (3111), (21111). The first aperiodic integer partition that is not totally aperiodic is (432211).

Cf. A000837, A018783, A047966, A098859, A100953, A305563, A319149, A319160, A319162, A319163, A319164, A319810.

totaperQ[m_]:=Or[UnsameQ@@m,And[GCD@@Length/@Split[Sort[m]]==1,totaperQ[Sort[Length/@Split[Sort[m]]]]]];
Table[Length[Select[IntegerPartitions[n],totaperQ]],{n,30}]

A319153 Number of integer partitions of n that reduce to 2, meaning their Heinz number maps to 2 under A304464.

Original entry on oeis.org

0, 2, 1, 3, 5, 7, 12, 17, 24, 33, 44, 57, 76, 100, 129, 168, 214, 282, 355, 462, 586, 755, 937, 1202, 1493, 1900, 2349, 2944, 3621, 4520, 5514, 6813, 8298, 10150, 12240, 14918, 17931, 21654, 25917, 31081, 37029, 44256, 52474, 62405, 73724, 87378, 102887

Offset: 1

Gus Wiseman, Sep 12 2018

nonn

Start with an integer partition y of n. Given a multiset, take the multiset of its multiplicities. Repeat until a multiset of size 1 is obtained. If this multiset is {2}, we say that y reduces to 2. For example, we have (3211) -> (211) -> (21) -> (11) -> (2), so (3211) reduces to 2.

			The a(7) = 12 partitions:
  (43), (52), (61),
  (322), (331), (511),
  (2221), (3211), (4111),
  (22111), (31111),
  (211111).

Cf. A000837, A098859, A181819, A182850, A304464, A304465, A304634, A305563, A317245, A319149.

Table[Length[Select[IntegerPartitions[n],NestWhile[Sort[Length/@Split[#]]&,#,Length[#]>1&]=={2}&]],{n,30}]

A334969 Heinz numbers of alternately strong integer partitions.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 25, 26, 27, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 41, 42, 43, 46, 47, 49, 50, 51, 53, 54, 55, 57, 58, 59, 61, 62, 64, 65, 66, 67, 69, 70, 71, 73, 74, 75, 77, 78, 79, 81, 82, 83

Offset: 1

Gus Wiseman, Jun 09 2020

nonn

First differs from A304678 in lacking 450.
First differs from A316529 (the totally strong version) in having 150.
A sequence is alternately strong if either it is empty, equal to (1), or its run-lengths are weakly decreasing (strong) and, when reversed, are themselves an alternately strong sequence.
The Heinz number of an integer partition (y_1,...,y_k) is prime(y_1)*...*prime(y_k). This gives a bijective correspondence between positive integers and integer partitions.

			The sequence does not contain 450, the Heinz number of (3,3,2,2,1), because, while the multiplicities are weakly decreasing, their reverse (1,2,2) does not have weakly decreasing multiplicities.

The co-strong version is A317257.
The case of reversed partitions is (also) A317257.
The total version is A316529.
These partitions are counted by A332339.
Totally co-strong partitions are counted by A332275.
Alternately co-strong compositions are counted by A332338.
Cf. A000041, A100883, A181819, A182850, A182857, A304660, A305563, A316496, A317256, A332292, A332340.

primeMS[n_]:=If[n==1,{},Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]];
altstrQ[q_]:=Or[q=={},q=={1},And[GreaterEqual@@Length/@Split[q],altstrQ[Reverse[Length/@Split[q]]]]];
Select[Range[100],altstrQ[Reverse[primeMS[#]]]&]

cp's OEIS Frontend

A305567 Irregular triangle where T(n,k) is the number of finite sets of positive integers with least common multiple n and greatest common divisor k, where k runs over all divisors of n.

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A305735 Number of integer partitions of n whose greatest common divisor is a prime number.

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A319179 Number of integer partitions of n that are relatively prime but not aperiodic. Number of integer partitions of n that are aperiodic but not relatively prime.

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A319299 Irregular triangle where T(n,k) is the number of integer partitions of n with GCD equal to the k-th divisor of n.

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A325332 Number of totally abnormal integer partitions of n.

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A305736 Number of integer partitions of n whose greatest common divisor is composite (nonprime and > 1).

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A319811 Number of totally aperiodic integer partitions of n.

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A319153 Number of integer partitions of n that reduce to 2, meaning their Heinz number maps to 2 under A304464.

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A334969 Heinz numbers of alternately strong integer partitions.

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