A359901
Triangle read by rows where T(n,k) is the number of integer partitions of n with median k = 1..n.
Original entry on oeis.org
1, 1, 1, 1, 0, 1, 2, 2, 0, 1, 3, 1, 0, 0, 1, 4, 2, 3, 0, 0, 1, 6, 3, 1, 0, 0, 0, 1, 8, 6, 2, 4, 0, 0, 0, 1, 11, 7, 3, 1, 0, 0, 0, 0, 1, 15, 10, 4, 2, 5, 0, 0, 0, 0, 1, 20, 13, 7, 3, 1, 0, 0, 0, 0, 0, 1, 26, 19, 11, 4, 2, 6, 0, 0, 0, 0, 0, 1
Offset: 1
Triangle begins:
1
1 1
1 0 1
2 2 0 1
3 1 0 0 1
4 2 3 0 0 1
6 3 1 0 0 0 1
8 6 2 4 0 0 0 1
11 7 3 1 0 0 0 0 1
15 10 4 2 5 0 0 0 0 1
20 13 7 3 1 0 0 0 0 0 1
26 19 11 4 2 6 0 0 0 0 0 1
35 24 14 5 3 1 0 0 0 0 0 0 1
45 34 17 8 4 2 7 0 0 0 0 0 0 1
58 42 23 12 5 3 1 0 0 0 0 0 0 0 1
For example, row n = 9 counts the following partitions:
(7,1,1) (5,2,2) (3,3,3) (4,4,1) . . . . (9)
(6,1,1,1) (6,2,1) (4,3,2)
(3,3,1,1,1) (3,2,2,2) (5,3,1)
(4,2,1,1,1) (4,2,2,1)
(5,1,1,1,1) (4,3,1,1)
(3,2,1,1,1,1) (2,2,2,2,1)
(4,1,1,1,1,1) (3,2,2,1,1)
(2,2,1,1,1,1,1)
(3,1,1,1,1,1,1)
(2,1,1,1,1,1,1,1)
(1,1,1,1,1,1,1,1,1)
Including half-steps gives
A359893.
The median statistic is ranked by
A360005(n)/2.
A240219 counts partitions w/ the same mean as median, complement
A359894.
-
Table[Length[Select[IntegerPartitions[n],Median[#]==k&]],{n,15},{k,n}]
A237984
Number of partitions of n whose mean is a part.
Original entry on oeis.org
1, 2, 2, 3, 2, 5, 2, 6, 5, 8, 2, 21, 2, 14, 22, 30, 2, 61, 2, 86, 67, 45, 2, 283, 66, 80, 197, 340, 2, 766, 2, 663, 543, 234, 703, 2532, 2, 388, 1395, 4029, 2, 4688, 2, 4476, 7032, 1005, 2, 17883, 2434, 9713, 7684, 14472, 2, 25348, 17562, 37829, 16786, 3721
Offset: 1
a(6) counts these partitions: 6, 33, 321, 222, 111111.
From _Gus Wiseman_, Sep 14 2019: (Start)
The a(1) = 1 through a(10) = 8 partitions (A = 10):
1 2 3 4 5 6 7 8 9 A
11 111 22 11111 33 1111111 44 333 55
1111 222 2222 432 22222
321 3221 531 32221
111111 4211 111111111 33211
11111111 42211
52111
1111111111
(End)
The Heinz numbers of these partitions are
A327473.
A similar sequence for subsets is
A065795.
Partitions without their mean are
A327472.
-
Table[Count[IntegerPartitions[n], p_ /; MemberQ[p, Mean[p]]], {n, 40}]
-
from sympy.utilities.iterables import partitions
def A237984(n): return sum(1 for s,p in partitions(n,size=True) if not n%s and n//s in p) # Chai Wah Wu, Sep 21 2023
A359902
Triangle read by rows where T(n,k) is the number of odd-length integer partitions of n with median k.
Original entry on oeis.org
1, 0, 1, 1, 0, 1, 1, 0, 0, 1, 2, 1, 0, 0, 1, 2, 2, 0, 0, 0, 1, 4, 2, 1, 0, 0, 0, 1, 4, 3, 2, 0, 0, 0, 0, 1, 7, 4, 3, 1, 0, 0, 0, 0, 1, 8, 6, 3, 2, 0, 0, 0, 0, 0, 1, 12, 8, 4, 3, 1, 0, 0, 0, 0, 0, 1, 14, 11, 5, 4, 2, 0, 0, 0, 0, 0, 0, 1
Offset: 1
Triangle begins:
1
0 1
1 0 1
1 0 0 1
2 1 0 0 1
2 2 0 0 0 1
4 2 1 0 0 0 1
4 3 2 0 0 0 0 1
7 4 3 1 0 0 0 0 1
8 6 3 2 0 0 0 0 0 1
12 8 4 3 1 0 0 0 0 0 1
14 11 5 4 2 0 0 0 0 0 0 1
21 14 8 4 3 1 0 0 0 0 0 0 1
24 20 10 5 4 2 0 0 0 0 0 0 0 1
34 25 15 6 5 3 1 0 0 0 0 0 0 0 1
For example, row n = 9 counts the following partitions:
(7,1,1) (5,2,2) (3,3,3) (4,4,1) . . . . (9)
(3,3,1,1,1) (6,2,1) (4,3,2)
(4,2,1,1,1) (2,2,2,2,1) (5,3,1)
(5,1,1,1,1) (3,2,2,1,1)
(2,2,1,1,1,1,1)
(3,1,1,1,1,1,1)
(1,1,1,1,1,1,1,1,1)
The median statistic is ranked by
A360005(n)/2.
A240219 counts partitions w/ the same mean as median, complement
A359894.
-
Table[Length[Select[IntegerPartitions[n],OddQ[Length[#]]&&Median[#]==k&]],{n,15},{k,n}]
A362608
Number of integer partitions of n having a unique mode.
Original entry on oeis.org
0, 1, 2, 2, 4, 5, 7, 11, 16, 21, 29, 43, 54, 78, 102, 131, 175, 233, 295, 389, 490, 623, 794, 1009, 1255, 1579, 1967, 2443, 3016, 3737, 4569, 5627, 6861, 8371, 10171, 12350, 14901, 18025, 21682, 26068, 31225, 37415, 44617, 53258, 63313, 75235, 89173, 105645
Offset: 0
The partition (3,3,2,1) has greatest multiplicity 2, and a unique part of multiplicity 2 (namely 3), so is counted under a(9).
The a(1) = 1 through a(7) = 11 partitions:
(1) (2) (3) (4) (5) (6) (7)
(11) (111) (22) (221) (33) (322)
(211) (311) (222) (331)
(1111) (2111) (411) (511)
(11111) (3111) (2221)
(21111) (3211)
(111111) (4111)
(22111)
(31111)
(211111)
(1111111)
For parts instead of multiplicities we have
A000041(n-1), ranks
A102750.
These partitions have ranks
A356862.
A275870 counts collapsible partitions.
A359893 counts partitions by median.
-
Table[Length[Select[IntegerPartitions[n],Length[Commonest[#]]==1&]],{n,0,30}]
-
seq(n) = my(A=O(x*x^n)); Vec(sum(m=1, n, sum(j=1, n\m, x^(j*m)*(1-x^j)/(1 - x^(j*m)), A)*prod(j=1, n\m, (1 - x^(j*m))/(1 - x^j) + A)/prod(j=n\m+1, n, 1 - x^j + A)), -(n+1)) \\ Andrew Howroyd, May 04 2023
A327476
Heinz numbers of integer partitions whose mean A326567/A326568 is not a part.
Original entry on oeis.org
1, 6, 10, 12, 14, 15, 18, 20, 21, 22, 24, 26, 28, 33, 34, 35, 36, 38, 39, 40, 42, 44, 45, 46, 48, 50, 51, 52, 54, 55, 56, 57, 58, 60, 62, 63, 65, 66, 68, 69, 70, 72, 74, 75, 76, 77, 78, 80, 82, 85, 86, 87, 88, 91, 92, 93, 94, 95, 96, 98, 99, 100, 102, 104, 106
Offset: 1
The sequence of terms together with their prime indices begins:
1: {}
6: {1,2}
10: {1,3}
12: {1,1,2}
14: {1,4}
15: {2,3}
18: {1,2,2}
20: {1,1,3}
21: {2,4}
22: {1,5}
24: {1,1,1,2}
26: {1,6}
28: {1,1,4}
33: {2,5}
34: {1,7}
35: {3,4}
36: {1,1,2,2}
38: {1,8}
39: {2,6}
40: {1,1,1,3}
The enumeration of these partitions by sum is given by
A327472.
Subsets whose mean is not an element are
A327471.
Cf.
A056239,
A067538,
A112798,
A114639,
A237984,
A240851,
A316413,
A324756,
A324758,
A326567/
A326568,
A327477.
-
primeMS[n_]:=If[n==1,{},Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]];
Select[Range[100],!MemberQ[primeMS[#],Mean[primeMS[#]]]&]
A362610
Number of integer partitions of n having a unique part of least multiplicity.
Original entry on oeis.org
0, 1, 2, 2, 4, 5, 7, 10, 13, 16, 23, 30, 35, 50, 61, 73, 95, 123, 139, 187, 216, 269, 328, 411, 461, 594, 688, 836, 980, 1211, 1357, 1703, 1936, 2330, 2697, 3253, 3649, 4468, 5057, 6005, 6841, 8182, 9149, 10976, 12341, 14508, 16447, 19380, 21611, 25553, 28628
Offset: 0
The partition (3,3,2,2,2,1,1,1) has least multiplicity 2, and only one part of multiplicity 2 (namely 3), so is counted under a(15).
The a(1) = 1 through a(8) = 13 partitions:
(1) (2) (3) (4) (5) (6) (7) (8)
(11) (111) (22) (221) (33) (322) (44)
(211) (311) (222) (331) (332)
(1111) (2111) (411) (511) (422)
(11111) (3111) (2221) (611)
(21111) (4111) (2222)
(111111) (22111) (5111)
(31111) (22211)
(211111) (41111)
(1111111) (221111)
(311111)
(2111111)
(11111111)
These partitions have ranks
A359178.
A275870 counts collapsible partitions.
A359893 counts partitions by median.
Cf.
A008284,
A053263,
A098859,
A237984,
A240219,
A304442,
A327472,
A353863,
A353864,
A353865,
A362612.
-
Table[Length[Select[IntegerPartitions[n],Count[Length/@Split[#],Min@@Length/@Split[#]]==1&]],{n,0,30}]
-
seq(n) = my(A=O(x*x^n)); Vec(sum(m=2, n+1, sum(j=1, n, x^(j*(m-1))/(1 + if(j*m<=n, x^(j*m)/(1-x^j) )) + A)*prod(j=1, n\m, 1 + x^(j*m)/(1 - x^j) + A)), -(n+1)) \\ Andrew Howroyd, May 04 2023
A359894
Number of integer partitions of n whose parts do not have the same mean as median.
Original entry on oeis.org
0, 0, 0, 0, 1, 3, 3, 10, 13, 20, 28, 49, 53, 93, 113, 145, 203, 287, 329, 479, 556, 724, 955, 1242, 1432, 1889, 2370, 2863, 3502, 4549, 5237, 6825, 8108, 9839, 12188, 14374, 16958, 21617, 25852, 30582, 36100, 44561, 51462, 63238, 73386, 85990, 105272, 124729
Offset: 0
The a(4) = 1 through a(8) = 13 partitions:
(211) (221) (411) (322) (332)
(311) (3111) (331) (422)
(2111) (21111) (421) (431)
(511) (521)
(2221) (611)
(3211) (4211)
(4111) (5111)
(22111) (22211)
(31111) (32111)
(211111) (41111)
(221111)
(311111)
(2111111)
The complement is counted by
A240219.
A008289 counts strict partitions by mean.
A359909 counts factorizations with the same mean as median, odd-len
A359910.
-
Table[Length[Select[IntegerPartitions[n],Mean[#]!=Median[#]&]],{n,0,30}]
A362607
Number of integer partitions of n with more than one mode.
Original entry on oeis.org
0, 0, 0, 1, 1, 2, 4, 4, 6, 9, 13, 13, 23, 23, 33, 45, 56, 64, 90, 101, 137, 169, 208, 246, 320, 379, 469, 567, 702, 828, 1035, 1215, 1488, 1772, 2139, 2533, 3076, 3612, 4333, 5117, 6113, 7168, 8557, 10003, 11862, 13899, 16385, 19109, 22525, 26198, 30729, 35736
Offset: 0
The partition (3,2,2,1,1) has greatest multiplicity 2, and two parts of multiplicity 2 (namely 1 and 2), so is counted under a(9).
The a(3) = 1 through a(9) = 9 partitions:
(21) (31) (32) (42) (43) (53) (54)
(41) (51) (52) (62) (63)
(321) (61) (71) (72)
(2211) (421) (431) (81)
(521) (432)
(3311) (531)
(621)
(32211)
(222111)
For parts instead of multiplicities we have
A002865.
These partitions have ranks
A362605.
A359893 counts partitions by median.
-
b:= proc(n, i, m, t) option remember; `if`(n=0, `if`(t=2, 1, 0), `if`(i<1, 0,
add(b(n-i*j, i-1, max(j, m), `if`(j>m, 1, `if`(j=m, 2, t))), j=0..n/i)))
end:
a:= n-> b(n$2, 0$2):
seq(a(n), n=0..51); # Alois P. Heinz, May 05 2024
-
Table[Length[Select[IntegerPartitions[n],Length[Commonest[#]]>1&]],{n,0,30}]
-
G_x(N)={my(x='x+O('x^(N-1)), Ib(k,j) = if(k>j,1,0), A_x(u)=sum(i=1,N-u, sum(j=u+1, N-u, (x^(i*(u+j))*(1-x^u)*(1-x^j))/((1-x^(u*i))*(1-x^(j*i))) * prod(k=1,N-i*(u+j), (1-x^(k*(i+Ib(k,j))))/(1-x^k)))));
concat([0,0,0],Vec(sum(u=1,N, A_x(u))))}
G_x(51) \\ John Tyler Rascoe, Apr 05 2024
A349156
Number of integer partitions of n whose mean is not an integer.
Original entry on oeis.org
1, 0, 0, 1, 1, 5, 3, 13, 11, 21, 28, 54, 31, 99, 111, 125, 165, 295, 259, 488, 425, 648, 933, 1253, 943, 1764, 2320, 2629, 2962, 4563, 3897, 6840, 6932, 9187, 11994, 12840, 12682, 21635, 25504, 28892, 28187, 44581, 42896, 63259, 66766, 74463, 104278, 124752
Offset: 0
The a(3) = 1 through a(8) = 11 partitions:
(21) (211) (32) (2211) (43) (332)
(41) (3111) (52) (422)
(221) (21111) (61) (431)
(311) (322) (521)
(2111) (331) (611)
(421) (22211)
(511) (32111)
(2221) (41111)
(3211) (221111)
(4111) (311111)
(22111) (2111111)
(31111)
(211111)
Below, "!" means either enumerative or set theoretical complement.
The version for nonempty subsets is !
A051293.
The version for distinct prime factors is
A176587, complement
A078174.
The multiplicative version (factorizations) is !
A326622, geometric !
A326028.
The conjugate is ranked by !
A326836.
The conjugate strict version is !
A326850.
These partitions are ranked by
A348551.
A327472 counts partitions not containing their mean, complement of
A237984.
Cf.
A001700,
A074761,
A098743,
A143773,
A175397,
A175761,
A298423,
A326027,
A326641,
A326842,
A326849,
A327778.
-
Table[Length[Select[IntegerPartitions[n],!IntegerQ[Mean[#]]&]],{n,0,30}]
A362612
Number of integer partitions of n such that the greatest part is the unique mode.
Original entry on oeis.org
0, 1, 2, 2, 3, 3, 4, 4, 6, 6, 7, 9, 10, 12, 15, 16, 19, 23, 26, 32, 37, 41, 48, 58, 65, 75, 88, 101, 115, 135, 151, 176, 200, 228, 261, 300, 336, 385, 439, 498, 561, 641, 717, 818, 921, 1036, 1166, 1321, 1477, 1667, 1867, 2099, 2346, 2640, 2944, 3303, 3684
Offset: 0
The a(1) = 1 through a(10) = 7 partitions (A = 10):
1 2 3 4 5 6 7 8 9 A
11 111 22 221 33 331 44 333 55
1111 11111 222 2221 332 441 442
111111 1111111 2222 3321 3331
22211 22221 22222
11111111 111111111 222211
1111111111
These partitions have ranks
A362616.
A275870 counts collapsible partitions.
A359893 counts partitions by median.
A362611 counts modes in prime factorization.
Cf.
A002865,
A008284,
A070003,
A098859,
A102750,
A237984,
A238478,
A238479,
A327472,
A362609,
A362610.
-
Table[Length[Select[IntegerPartitions[n],Commonest[#]=={Max[#]}&]],{n,0,30}]
-
A_x(N)={my(x='x+O('x^N), g=sum(i=1, N, sum(j=1, N/i, x^(i*j)*prod(k=1,i-1,(1-x^(j*k))/(1-x^k))))); concat([0],Vec(g))}
A_x(60) \\ John Tyler Rascoe, Apr 03 2024
Showing 1-10 of 47 results.
Comments