A365541
Irregular triangle read by rows where T(n,k) is the number of subsets of {1..n} containing two distinct elements summing to k = 3..2n-1.
Original entry on oeis.org
1, 2, 2, 2, 4, 4, 7, 4, 4, 8, 8, 14, 14, 14, 8, 8, 16, 16, 28, 28, 37, 28, 28, 16, 16, 32, 32, 56, 56, 74, 74, 74, 56, 56, 32, 32, 64, 64, 112, 112, 148, 148, 175, 148, 148, 112, 112, 64, 64, 128, 128, 224, 224, 296, 296, 350, 350, 350, 296, 296, 224, 224, 128, 128
Offset: 2
Triangle begins:
1
2 2 2
4 4 7 4 4
8 8 14 14 14 8 8
16 16 28 28 37 28 28 16 16
32 32 56 56 74 74 74 56 56 32 32
Row n = 4 counts the following subsets:
{1,2} {1,3} {1,4} {2,4} {3,4}
{1,2,3} {1,2,3} {2,3} {1,2,4} {1,3,4}
{1,2,4} {1,3,4} {1,2,3} {2,3,4} {2,3,4}
{1,2,3,4} {1,2,3,4} {1,2,4} {1,2,3,4} {1,2,3,4}
{1,3,4}
{2,3,4}
{1,2,3,4}
The case counting only length-2 subsets is
A008967.
Column k = n + 1 appears to be
A167762.
The version for all subsets (instead of just pairs) is
A365381.
A000009 counts subsets summing to n.
A046663 counts partitions with no submultiset summing to k, strict
A365663.
A365543 counts partitions with a submultiset summing to k, strict
A365661.
-
Table[Length[Select[Subsets[Range[n]], MemberQ[Total/@Subsets[#,{2}],k]&]], {n,2,11}, {k,3,2n-1}]
A365831
Number of incomplete strict integer partitions of n, meaning not every number from 0 to n is the sum of some submultiset.
Original entry on oeis.org
0, 0, 1, 1, 2, 3, 3, 4, 6, 8, 9, 11, 13, 16, 21, 25, 31, 36, 43, 50, 59, 69, 82, 96, 113, 131, 155, 179, 208, 239, 276, 315, 362, 414, 472, 539, 614, 698, 795, 902, 1023, 1158, 1311, 1479, 1672, 1881, 2118, 2377, 2671, 2991, 3354, 3748, 4194, 4679, 5223, 5815
Offset: 0
The strict partition (14,5,4,2,1) has no subset summing to 13 so is counted under a(26).
The a(2) = 1 through a(10) = 9 strict partitions:
(2) (3) (4) (5) (6) (7) (8) (9) (10)
(3,1) (3,2) (4,2) (4,3) (5,3) (5,4) (6,4)
(4,1) (5,1) (5,2) (6,2) (6,3) (7,3)
(6,1) (7,1) (7,2) (8,2)
(4,3,1) (8,1) (9,1)
(5,2,1) (4,3,2) (5,3,2)
(5,3,1) (5,4,1)
(6,2,1) (6,3,1)
(7,2,1)
A046663 counts partitions w/o a submultiset summing to k, strict
A365663.
A325799 counts non-subset-sums of prime indices.
A365543 counts partitions with a submultiset summing to k, strict
A365661.
-
nmz[y_]:=Complement[Range[Total[y]], Total/@Subsets[y]];
Table[Length[Select[IntegerPartitions[n], UnsameQ@@#&&Length[nmz[#]]>0&]],{n,0,15}]
A367213
Number of integer partitions of n whose length (number of parts) is not equal to the sum of any submultiset.
Original entry on oeis.org
0, 0, 1, 1, 2, 2, 5, 4, 7, 8, 12, 13, 19, 21, 29, 33, 45, 49, 67, 73, 97, 108, 139, 152, 196, 217, 274, 303, 379, 420, 523, 579, 709, 786, 960, 1061, 1285, 1423, 1714, 1885, 2265, 2498, 2966, 3280, 3881, 4268, 5049, 5548, 6507, 7170, 8391, 9194, 10744, 11778, 13677
Offset: 0
The a(3) = 1 through a(9) = 8 partitions:
(3) (4) (5) (6) (7) (8) (9)
(3,1) (4,1) (3,3) (4,3) (4,4) (5,4)
(5,1) (6,1) (5,3) (6,3)
(2,2,2) (5,1,1) (7,1) (8,1)
(4,1,1) (4,2,2) (4,4,1)
(6,1,1) (5,2,2)
(5,1,1,1) (7,1,1)
(6,1,1,1)
The following sequences count and rank integer partitions and finite sets according to whether their length is a subset-sum or linear combination of the parts. The current sequence is starred.
sum-full sum-free comb-full comb-free
-------------------------------------------
Triangles:
A046663 counts partitions of n without a subset-sum k, strict
A365663.
-
Table[Length[Select[IntegerPartitions[n], FreeQ[Total/@Subsets[#], Length[#]]&]], {n,0,10}]
A367224
Numbers m with a divisor whose prime indices sum to bigomega(m).
Original entry on oeis.org
1, 2, 4, 6, 8, 9, 12, 15, 16, 18, 20, 21, 24, 30, 32, 33, 36, 39, 40, 42, 45, 48, 50, 51, 54, 56, 57, 60, 64, 66, 69, 70, 72, 75, 78, 80, 81, 84, 87, 90, 93, 96, 100, 102, 105, 108, 110, 111, 112, 114, 120, 123, 125, 126, 128, 129, 130, 132, 135, 138, 140, 141
Offset: 1
The prime indices of 24 are {1,1,1,2} with submultiset {1,1,2} summing to 4, so 24 is in the sequence.
The terms together with their prime indices begin:
1: {}
2: {1}
4: {1,1}
6: {1,2}
8: {1,1,1}
9: {2,2}
12: {1,1,2}
15: {2,3}
16: {1,1,1,1}
18: {1,2,2}
20: {1,1,3}
21: {2,4}
24: {1,1,1,2}
30: {1,2,3}
32: {1,1,1,1,1}
The following sequences count and rank integer partitions and finite sets according to whether their length is a subset-sum or linear combination of the parts. The current sequence is starred.
sum-full sum-free comb-full comb-free
-------------------------------------------
Triangles:
A046663 counts partitions of n without a subset-sum k, strict
A365663.
-
prix[n_]:=If[n==1, {}, Flatten[Cases[FactorInteger[n], {p_,k_}:>Table[PrimePi[p], {k}]]]];
Select[Range[100], MemberQ[Total/@prix/@Divisors[#], PrimeOmega[#]]&]
A367225
Numbers m without a divisor whose prime indices sum to bigomega(m).
Original entry on oeis.org
3, 5, 7, 10, 11, 13, 14, 17, 19, 22, 23, 25, 26, 27, 28, 29, 31, 34, 35, 37, 38, 41, 43, 44, 46, 47, 49, 52, 53, 55, 58, 59, 61, 62, 63, 65, 67, 68, 71, 73, 74, 76, 77, 79, 82, 83, 85, 86, 88, 89, 91, 92, 94, 95, 97, 98, 99, 101, 103, 104, 106, 107, 109, 113
Offset: 1
The prime indices of 24 are {1,1,1,2} with submultiset {1,1,2} summing to 4, so 24 is not in the sequence.
The terms together with their prime indices begin:
3: {2} 29: {10} 58: {1,10}
5: {3} 31: {11} 59: {17}
7: {4} 34: {1,7} 61: {18}
10: {1,3} 35: {3,4} 62: {1,11}
11: {5} 37: {12} 63: {2,2,4}
13: {6} 38: {1,8} 65: {3,6}
14: {1,4} 41: {13} 67: {19}
17: {7} 43: {14} 68: {1,1,7}
19: {8} 44: {1,1,5} 71: {20}
22: {1,5} 46: {1,9} 73: {21}
23: {9} 47: {15} 74: {1,12}
25: {3,3} 49: {4,4} 76: {1,1,8}
26: {1,6} 52: {1,1,6} 77: {4,5}
27: {2,2,2} 53: {16} 79: {22}
28: {1,1,4} 55: {3,5} 82: {1,13}
The following sequences count and rank integer partitions and finite sets according to whether their length is a subset-sum or linear combination of the parts. The current sequence is starred.
sum-full sum-free comb-full comb-free
-------------------------------------------
Triangles:
A046663 counts partitions of n without a subset-sum k, strict
A365663.
-
prix[n_]:=If[n==1,{}, Flatten[Cases[FactorInteger[n], {p_,k_}:>Table[PrimePi[p],{k}]]]];
Select[Range[100], FreeQ[Total/@prix/@Divisors[#], PrimeOmega[#]]&]
A365925
Number of subset-sums of strict integer partitions of n.
Original entry on oeis.org
1, 2, 2, 6, 6, 10, 17, 22, 29, 42, 59, 74, 102, 130, 171, 226, 281, 356, 454, 566, 699, 896, 1080, 1342, 1637, 2006, 2413, 2962, 3548, 4286, 5114, 6148, 7272, 8738, 10268, 12224, 14387, 16996, 19863, 23450, 27257, 31984, 37187, 43364, 50173, 58428, 67322
Offset: 0
The a(6) = 17 ways, showing each strict partition and its subset-sums:
(6): 0,6
(51): 0,1,5,6
(42): 0,2,4,6
(321): 0,1,2,3,4,5,6
A367212
Number of integer partitions of n whose length (number of parts) is equal to the sum of some submultiset.
Original entry on oeis.org
1, 1, 1, 2, 3, 5, 6, 11, 15, 22, 30, 43, 58, 80, 106, 143, 186, 248, 318, 417, 530, 684, 863, 1103, 1379, 1741, 2162, 2707, 3339, 4145, 5081, 6263, 7640, 9357, 11350, 13822, 16692, 20214, 24301, 29300, 35073, 42085, 50208, 59981, 71294, 84866, 100509, 119206
Offset: 0
The partition (3,2,1,1) has submultisets (3,1) or (2,1,1) with sum 4, so is counted under a(7).
The a(1) = 1 through a(8) = 15 partitions:
(1) (11) (21) (22) (32) (42) (52) (62)
(111) (211) (221) (321) (322) (332)
(1111) (311) (2211) (331) (431)
(2111) (3111) (421) (521)
(11111) (21111) (2221) (2222)
(111111) (3211) (3221)
(4111) (3311)
(22111) (4211)
(31111) (22211)
(211111) (32111)
(1111111) (41111)
(221111)
(311111)
(2111111)
(11111111)
The following sequences count and rank integer partitions and finite sets according to whether their length is a subset-sum or linear combination of the parts. The current sequence is starred.
sum-full sum-free comb-full comb-free
-------------------------------------------
Triangles:
-
Table[Length[Select[IntegerPartitions[n], MemberQ[Total/@Subsets[#], Length[#]]&]], {n,0,10}]
A367214
Number of strict integer partitions of n whose length (number of parts) is equal to the sum of some submultiset.
Original entry on oeis.org
1, 1, 0, 1, 0, 1, 2, 2, 3, 4, 5, 5, 7, 8, 10, 12, 14, 17, 21, 25, 30, 36, 43, 51, 60, 71, 83, 97, 113, 132, 153, 178, 205, 238, 272, 315, 360, 413, 471, 539, 613, 698, 792, 899, 1018, 1153, 1302, 1470, 1658, 1867, 2100, 2362, 2652, 2974, 3335, 3734, 4178, 4672
Offset: 0
The strict partition (6,4,3,2,1) has submultisets {1,4} and {2,3} with sum 5 so is counted under a(16).
The a(1) = 1 through a(10) = 5 strict partitions:
(1) . (2,1) . (3,2) (4,2) (5,2) (6,2) (7,2) (8,2)
(3,2,1) (4,2,1) (4,3,1) (4,3,2) (5,3,2)
(5,2,1) (5,3,1) (6,3,1)
(6,2,1) (7,2,1)
(4,3,2,1)
The following sequences count and rank integer partitions and finite sets according to whether their length is a subset-sum or linear combination of the parts. The current sequence is starred.
sum-full sum-free comb-full comb-free
-------------------------------------------
A240855 counts strict partitions whose length is a part, complement
A240861.
Triangles:
A365661 counts strict partitions with a subset-sum k, non-strict
A365543.
Cf.
A002865,
A126796,
A237113,
A237668,
A238628,
A363225,
A364346,
A364350,
A364533,
A365311,
A365922.
-
Table[Length[Select[IntegerPartitions[n], UnsameQ@@#&&MemberQ[Total/@Subsets[#], Length[#]]&]], {n,0,30}]
A367215
Number of strict integer partitions of n whose length (number of parts) is not equal to the sum of any subset.
Original entry on oeis.org
0, 0, 1, 1, 2, 2, 2, 3, 3, 4, 5, 7, 8, 10, 12, 15, 18, 21, 25, 29, 34, 40, 46, 53, 62, 71, 82, 95, 109, 124, 143, 162, 185, 210, 240, 270, 308, 347, 393, 443, 500, 562, 634, 711, 798, 895, 1002, 1120, 1252, 1397, 1558, 1735, 1930, 2146, 2383, 2644, 2930, 3245
Offset: 0
The a(2) = 1 through a(11) = 7 strict partitions:
(2) (3) (4) (5) (6) (7) (8) (9) (10) (11)
(3,1) (4,1) (5,1) (4,3) (5,3) (5,4) (6,4) (6,5)
(6,1) (7,1) (6,3) (7,3) (7,4)
(8,1) (9,1) (8,3)
(5,4,1) (10,1)
(5,4,2)
(6,4,1)
The a(2) = 1 through a(15) = 15 strict partitions (A..F = 10..15):
2 3 4 5 6 7 8 9 A B C D E F
31 41 51 43 53 54 64 65 75 76 86 87
61 71 63 73 74 84 85 95 96
81 91 83 93 94 A4 A5
541 A1 B1 A3 B3 B4
542 642 C1 D1 C3
641 651 652 752 E1
741 742 761 654
751 842 762
841 851 852
941 861
6521 942
951
A41
7521
The following sequences count and rank integer partitions and finite sets according to whether their length is a subset-sum or linear combination of the parts. The current sequence is starred.
sum-full sum-free comb-full comb-free
-------------------------------------------
A124506 appears to count combination-free subsets, differences of
A326083.
A240861 counts strict partitions with length not a part, complement
A240855.
Triangles:
A365661 counts strict partitions with a subset-sum k, non-strict
A365543.
A365663 counts strict partitions without a subset-sum k, non-strict
A046663.
-
Table[Length[Select[IntegerPartitions[n], UnsameQ@@#&&FreeQ[Total/@Subsets[#], Length[#]]&]], {n,0,30}]
A365918
Number of distinct non-subset-sums of integer partitions of n.
Original entry on oeis.org
0, 1, 2, 6, 8, 19, 24, 46, 60, 101, 124, 206, 250, 378, 462, 684, 812, 1165, 1380, 1927, 2268, 3108, 3606, 4862, 5648, 7474, 8576, 11307, 12886, 16652, 19050, 24420, 27584, 35225, 39604, 49920, 56370, 70540, 78608, 98419, 109666, 135212, 151176, 185875, 205308
Offset: 1
The a(6) = 19 ways, showing each partition and its non-subset-sums:
(6): 1,2,3,4,5
(51): 2,3,4
(42): 1,3,5
(411): 3
(33): 1,2,4,5
(321):
(3111):
(222): 1,3,5
(2211):
(21111):
(111111):
The zero-full complement (subset-sums) is
A304792.
A365543 counts partitions with a submultiset summing to k, strict
A365661.
-
Table[Total[Length[Complement[Range[n],Total/@Subsets[#]]]&/@IntegerPartitions[n]],{n,10}]
-
# uses A304792_T
from sympy import npartitions
def A365918(n): return (n+1)*npartitions(n)-A304792_T(n,n,(0,),1) # Chai Wah Wu, Sep 25 2023
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