A318361
Number of strict set multipartitions (sets of sets) of a multiset whose multiplicities are the prime indices of n.
Original entry on oeis.org
1, 1, 0, 2, 0, 1, 0, 5, 1, 0, 0, 4, 0, 0, 0, 15, 0, 5, 0, 1, 0, 0, 0, 16, 0, 0, 8, 0, 0, 2, 0, 52, 0, 0, 0, 23, 0, 0, 0, 7, 0, 0, 0, 0, 5, 0, 0, 68, 0, 1, 0, 0, 0, 40, 0, 1, 0, 0, 0, 14, 0, 0, 1, 203, 0, 0, 0, 0, 0, 0, 0, 111, 0, 0, 4, 0, 0, 0, 0, 41, 80, 0, 0
Offset: 1
The a(24) = 16 sets of sets with multiset union {1,1,2,3,4}:
{{1},{1,2,3,4}}
{{1,2},{1,3,4}}
{{1,3},{1,2,4}}
{{1,4},{1,2,3}}
{{1},{2},{1,3,4}}
{{1},{3},{1,2,4}}
{{1},{4},{1,2,3}}
{{1},{1,2},{3,4}}
{{1},{1,3},{2,4}}
{{1},{1,4},{2,3}}
{{2},{1,3},{1,4}}
{{3},{1,2},{1,4}}
{{4},{1,2},{1,3}}
{{1},{2},{3},{1,4}}
{{1},{2},{4},{1,3}}
{{1},{3},{4},{1,2}}
-
nrmptn[n_]:=Join@@MapIndexed[Table[#2[[1]],{#1}]&,If[n==1,{},Flatten[Cases[FactorInteger[n]//Reverse,{p_,k_}:>Table[PrimePi[p],{k}]]]]];
sqfacs[n_]:=If[n<=1,{{}},Join@@Table[Map[Prepend[#,d]&,Select[sqfacs[n/d],Min@@#>d&]],{d,Select[Rest[Divisors[n]],SquareFreeQ]}]];
Table[Length[sqfacs[Times@@Prime/@nrmptn[n]]],{n,90}]
-
permcount(v) = {my(m=1, s=0, k=0, t); for(i=1, #v, t=v[i]; k=if(i>1&&t==v[i-1], k+1, 1); m*=t*k; s+=t); s!/m}
sig(n)={my(f=factor(n)); concat(vector(#f~, i, vector(f[i, 2], j, primepi(f[i, 1]))))}
count(sig)={my(r=0, A=O(x*x^vecmax(sig))); for(n=1, vecsum(sig)+1, my(s=0); forpart(p=n, my(q=prod(i=1, #p, 1 + x^p[i] + A)); s+=prod(i=1, #sig, polcoef(q, sig[i]))*(-1)^#p*permcount(p)); r+=(-1)^n*s/n!); r/2}
a(n)={if(n==1, 1, my(s=sig(n)); if(#s==1, s[1]==1, count(sig(n))))} \\ Andrew Howroyd, Dec 18 2018
A321742
Irregular triangle read by rows where T(H(u),H(v)) is the coefficient of m(v) in e(u), where H is Heinz number, m is monomial symmetric functions, and e is elementary symmetric functions.
Original entry on oeis.org
1, 1, 0, 1, 1, 2, 0, 0, 1, 0, 1, 3, 0, 0, 0, 0, 1, 1, 3, 6, 0, 1, 0, 2, 6, 0, 0, 0, 1, 4, 0, 0, 0, 0, 0, 0, 1, 0, 2, 1, 5, 12, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 5, 0, 0, 0, 1, 0, 3, 10, 1, 6, 4, 12, 24, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
Offset: 1
Triangle begins:
1
1
0 1
1 2
0 0 1
0 1 3
0 0 0 0 1
1 3 6
0 1 0 2 6
0 0 0 1 4
0 0 0 0 0 0 1
0 2 1 5 12
0 0 0 0 0 0 0 0 0 0 1
0 0 0 0 0 1 5
0 0 0 1 0 3 10
1 6 4 12 24
0 0 0 0 0 0 0 0 0 0 0 0 0 0 1
0 0 1 5 2 12 30
For example, row 12 gives: e(211) = 2m(22) + m(31) + 5m(211) + 12m(1111).
Cf.
A008480,
A049311,
A056239,
A116540,
A124794,
A124795,
A300121,
A319193,
A321738,
A321742-
A321765,
A321854.
-
primeMS[n_]:=If[n==1,{},Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]];
sps[{}]:={{}};sps[set:{i_,_}]:=Join@@Function[s,Prepend[#,s]&/@sps[Complement[set,s]]]/@Cases[Subsets[set],{i,_}];
mps[set_]:=Union[Sort[Sort/@(#/.x_Integer:>set[[x]])]&/@sps[Range[Length[set]]]];
nrmptn[n_]:=Join@@MapIndexed[Table[#2[[1]],{#1}]&,If[n==1,{},Flatten[Cases[FactorInteger[n]//Reverse,{p_,k_}:>Table[PrimePi[p],{k}]]]]];
Table[Table[Sum[Times@@Factorial/@Length/@Split[Sort[Length/@mtn,Greater]]/Times@@Factorial/@Length/@Split[mtn],{mtn,Select[mps[nrmptn[n]],And[And@@UnsameQ@@@#,Sort[Length/@#]==primeMS[k]]&]}],{k,Sort[Times@@Prime/@#&/@IntegerPartitions[Total[primeMS[n]]]]}],{n,18}]
A381431
Heinz number of the section-sum partition of the prime indices of n.
Original entry on oeis.org
1, 2, 3, 4, 5, 5, 7, 8, 9, 7, 11, 10, 13, 11, 11, 16, 17, 15, 19, 14, 13, 13, 23, 20, 25, 17, 27, 22, 29, 13, 31, 32, 17, 19, 17, 25, 37, 23, 19, 28, 41, 17, 43, 26, 33, 29, 47, 40, 49, 35, 23, 34, 53, 45, 19, 44, 29, 31, 59, 26, 61, 37, 39, 64, 23, 19, 67, 38
Offset: 1
Prime indices of 180 are (3,2,2,1,1), with section-sum partition (6,3), so a(180) = 65.
The terms together with their prime indices begin:
1: {}
2: {1}
3: {2}
4: {1,1}
5: {3}
5: {3}
7: {4}
8: {1,1,1}
9: {2,2}
7: {4}
11: {5}
10: {1,3}
13: {6}
11: {5}
11: {5}
16: {1,1,1,1}
Taking length instead of sum in the definition gives
A238745, conjugate
A181819.
A003963 gives product of prime indices.
A122111 represents conjugation in terms of Heinz numbers.
Cf.
A000720,
A003557,
A005117,
A047966,
A051903,
A066328,
A091602,
A116861,
A130091,
A212166,
A380955.
-
prix[n_]:=If[n==1,{},Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]];
egs[y_]:=If[y=={},{},Table[Total[Select[Union[y],Count[y,#]>=i&]],{i,Max@@Length/@Split[y]}]];
Table[Times@@Prime/@egs[prix[n]],{n,100}]
A306005
Number of non-isomorphic set-systems of weight n with no singletons.
Original entry on oeis.org
1, 0, 1, 1, 3, 4, 12, 19, 51, 106, 274, 647, 1773, 4664, 13418, 38861, 118690, 370588, 1202924, 4006557, 13764760, 48517672, 175603676, 651026060, 2471150365, 9590103580, 38023295735, 153871104726, 635078474978, 2671365285303, 11444367926725, 49903627379427
Offset: 0
Non-isomorphic representatives of the a(6) = 12 set-systems:
{{1,2,3,4,5,6}}
{{1,2},{3,4,5,6}}
{{1,5},{2,3,4,5}}
{{3,4},{1,2,3,4}}
{{1,2,3},{4,5,6}}
{{1,2,5},{3,4,5}}
{{1,3,4},{2,3,4}}
{{1,2},{1,3},{2,3}}
{{1,2},{3,4},{5,6}}
{{1,2},{3,5},{4,5}}
{{1,3},{2,4},{3,4}}
{{1,4},{2,4},{3,4}}
The complement is counted by
A330053.
Cf.
A007716,
A034691,
A048143,
A049311,
A054921,
A116540,
A283877,
A293606,
A293607,
A304867,
A305999,
A305854-
A305857,
A306005-
A306008.
-
WeighT(v)={Vec(exp(x*Ser(dirmul(v, vector(#v, n, (-1)^(n-1)/n))))-1, -#v)}
permcount(v) = {my(m=1, s=0, k=0, t); for(i=1, #v, t=v[i]; k=if(i>1&&t==v[i-1], k+1, 1); m*=t*k; s+=t); s!/m}
K(q, t, k)={WeighT(Vec(sum(j=1, #q, my(g=gcd(t, q[j])); g*x^(q[j]/g)) + O(x*x^k), -k)) - Vec(sum(j=1, #q, if(t%q[j]==0, q[j])) + O(x*x^k), -k)}
a(n)={if(n==0, 1, my(s=0); forpart(q=n, my(g=sum(t=1, n, subst(x*Ser(K(q, t, n\t)/t),x,x^t) )); s+=permcount(q)*polcoef(exp(g - subst(g,x,x^2)), n)); s/n!)} \\ Andrew Howroyd, Jan 16 2024
A317081
Number of integer partitions of n whose multiplicities cover an initial interval of positive integers.
Original entry on oeis.org
1, 1, 1, 2, 3, 5, 5, 9, 11, 16, 20, 30, 34, 50, 58, 79, 96, 129, 152, 203, 243, 307, 375, 474, 563, 707, 850, 1042, 1246, 1532, 1815, 2215, 2632, 3173, 3765, 4525, 5323, 6375, 7519, 8916, 10478, 12414, 14523, 17133, 20034, 23488, 27422, 32090, 37285, 43511, 50559
Offset: 0
The a(1) = 1 through a(9) = 16 partitions:
(1) (2) (3) (4) (5) (6) (7) (8) (9)
(21) (31) (32) (42) (43) (53) (54)
(211) (41) (51) (52) (62) (63)
(221) (321) (61) (71) (72)
(311) (411) (322) (332) (81)
(331) (422) (432)
(421) (431) (441)
(511) (521) (522)
(3211) (611) (531)
(3221) (621)
(4211) (711)
(3321)
(4221)
(4311)
(5211)
(32211)
The case with parts also covering an initial interval is
A317088.
These partitions are ranked by
A317090.
A047966 counts partitions with constant section-sums.
A048767 interchanges prime indices and prime multiplicities (Look-and-Say), see
A048768.
A055932 lists numbers whose prime indices cover an initial interval.
A116540 counts normal set multipartitions.
A381436 lists the section-sum partition of prime indices.
A381440 lists the Look-and-Say partition of prime indices.
-
normalQ[m_]:=Union[m]==Range[Max[m]];
Table[Length[Select[IntegerPartitions[n],normalQ[Length/@Split[#]]&]],{n,30}]
-
from sympy.utilities.iterables import partitions
def A317081(n):
if n == 0:
return 1
c = 0
for d in partitions(n):
s = set(d.values())
if len(s) == max(s):
c += 1
return c # Chai Wah Wu, Jun 22 2020
A381718
Number of normal multiset partitions of weight n into sets with distinct sums.
Original entry on oeis.org
1, 1, 2, 6, 23, 106, 549, 3184, 20353, 141615, 1063399, 8554800, 73281988, 665141182, 6369920854, 64133095134, 676690490875, 7462023572238, 85786458777923, 1025956348473929, 12739037494941490
Offset: 0
The a(1) = 1 through a(3) = 6 multiset partitions:
{{1}} {{1,2}} {{1,2,3}}
{{1},{2}} {{1},{1,2}}
{{1},{2,3}}
{{2},{1,2}}
{{2},{1,3}}
{{1},{2},{3}}
The a(4) = 23 factorizations:
2*3*6 5*30 3*30 2*30 210
10*15 6*15 6*10 2*105
2*5*15 2*3*15 2*3*10 3*70
3*5*10 5*42
7*30
6*35
10*21
2*3*35
2*5*21
2*7*15
3*5*14
2*3*5*7
Without distinct sums we have
A116540 (normal set multipartitions).
Twice-partitions of this type are counted by
A279785.
Without strict blocks we have
A326519.
Factorizations of this type are counted by
A381633.
For constant instead of strict blocks we have
A382203.
For distinct sizes instead of sums we have
A382428, non-strict blocks
A326517.
For equal instead of distinct block-sums we have
A382429, non-strict blocks
A326518.
Cf.
A000110,
A007716,
A050320,
A255903,
A275780,
A317532,
A317583,
A321469,
A381635,
A382204,
A382214,
A382216.
-
allnorm[n_Integer]:=Function[s,Array[Count[s,y_/;y<=#]+1&,n]]/@Subsets[Range[n-1]+1];
sps[{}]:={{}};sps[set:{i_,_}]:=Join@@Function[s,Prepend[#,s]&/@sps[Complement[set,s]]]/@Cases[Subsets[set],{i,_}];
mps[mset_]:=Union[Sort[Sort/@(#/.x_Integer:>mset[[x]])]&/@sps[Range[Length[mset]]]];
Table[Length[Join@@(Select[mps[#],UnsameQ@@Total/@#&&And@@UnsameQ@@@#&]&/@allnorm[n])],{n,0,5}]
A383708
Number of integer partitions of n such that it is possible to choose a family of pairwise disjoint strict integer partitions, one of each part.
Original entry on oeis.org
1, 1, 2, 2, 3, 5, 5, 7, 8, 13, 14, 18, 22, 27, 36, 41, 50, 61, 73, 86
Offset: 0
For y = (3,3) we can choose disjoint strict partitions ((2,1),(3)), so (3,3) is counted under a(6).
The a(1) = 1 through a(9) = 8 partitions:
(1) (2) (3) (4) (5) (6) (7) (8) (9)
(2,1) (3,1) (3,2) (3,3) (4,3) (4,4) (5,4)
(4,1) (4,2) (5,2) (5,3) (6,3)
(5,1) (6,1) (6,2) (7,2)
(3,2,1) (4,2,1) (7,1) (8,1)
(4,3,1) (4,3,2)
(5,2,1) (5,3,1)
(6,2,1)
These partitions have Heinz numbers
A382913.
The number of such families for each Heinz number is
A383706.
A098859 counts partitions with distinct multiplicities, compositions
A242882.
Cf.
A044813,
A047966,
A089259,
A116540,
A091602,
A130091,
A317141,
A351013,
A381441,
A382771,
A383013.
-
pof[y_]:=Select[Join@@@Tuples[IntegerPartitions/@y], UnsameQ@@#&];
Table[Length[Select[IntegerPartitions[n], pof[#]!={}&]],{n,15}]
A381806
Numbers that cannot be written as a product of squarefree numbers with distinct sums of prime indices.
Original entry on oeis.org
4, 8, 9, 16, 24, 25, 27, 32, 40, 48, 49, 54, 56, 64, 72, 80, 81, 88, 96, 104, 108, 112, 121, 125, 128, 135, 136, 144, 152, 160, 162, 169, 176, 184, 189, 192, 200, 208, 216, 224, 232, 240, 243, 248, 250, 256, 272, 288, 289, 296, 297, 304, 320, 324, 328, 336
Offset: 1
There are 4 factorizations of 18000 into squarefree numbers:
(2*2*3*5*10*30)
(2*2*5*6*10*15)
(2*2*10*15*30)
(2*5*6*10*30)
but none of these has all distinct sums of prime indices, so 18000 is in the sequence.
Strongly normal multisets of this type are counted by
A292444.
For more on set multipartitions with distinct sums see
A279785,
A381718.
A003963 gives product of prime indices.
-
hwt[n_]:=Total[Cases[FactorInteger[n],{p_,k_}:>PrimePi[p]*k]];
sqfics[n_]:=If[n<=1,{{}},Join@@Table[Map[Prepend[#,d]&,Select[sqfics[n/d],Min@@#>=d&]],{d,Select[Rest[Divisors[n]],SquareFreeQ]}]]
Select[Range[nn],Length[Select[sqfics[#],UnsameQ@@hwt/@#&]]==0&]
A306006
Number of non-isomorphic intersecting set-systems of weight n.
Original entry on oeis.org
1, 1, 1, 2, 3, 5, 10, 16, 30, 57, 109, 209, 431, 873, 1850, 3979, 8819, 19863
Offset: 0
Non-isomorphic representatives of the a(6) = 10 set-systems:
{{1,2,3,4,5,6}}
{{5},{1,2,3,4,5}}
{{1,5},{2,3,4,5}}
{{3,4},{1,2,3,4}}
{{1,2,5},{3,4,5}}
{{1,3,4},{2,3,4}}
{{3},{2,3},{1,2,3}}
{{4},{1,4},{2,3,4}}
{{1,2},{1,3},{2,3}}
{{1,4},{2,4},{3,4}}
Cf.
A007716,
A034691,
A048143,
A049311,
A116540,
A283877,
A293606,
A293607,
A304867,
A305999,
A305854-
A305857,
A306005-
A306008.
A383710
Number of integer partitions of n such that it is not possible to choose a family of pairwise disjoint strict integer partitions, one of each part.
Original entry on oeis.org
0, 0, 1, 1, 3, 4, 6, 10, 15, 22, 29, 42, 59, 79, 108, 140, 190, 247, 324, 417, 541
Offset: 0
For y = (3,3) we can choose disjoint strict partitions ((2,1),(3)), so (3,3) is not counted under a(6).
The a(2) = 1 through a(8) = 15 partitions:
(11) (111) (22) (221) (222) (322) (332)
(211) (311) (411) (331) (422)
(1111) (2111) (2211) (511) (611)
(11111) (3111) (2221) (2222)
(21111) (3211) (3221)
(111111) (4111) (3311)
(22111) (4211)
(31111) (5111)
(211111) (22211)
(1111111) (32111)
(41111)
(221111)
(311111)
(2111111)
(11111111)
These partitions have Heinz numbers
A382912.
The number of such families for each Heinz number is
A383706.
A098859 counts partitions with distinct multiplicities, compositions
A242882.
-
pof[y_]:=Select[Join@@@Tuples[IntegerPartitions/@y], UnsameQ@@#&];
Table[Length[Select[IntegerPartitions[n], pof[#]=={}&]], {n,0,15}]
Comments