cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-10 of 13 results. Next

A126796 Number of complete partitions of n.

Original entry on oeis.org

1, 1, 1, 2, 2, 4, 5, 8, 10, 16, 20, 31, 39, 55, 71, 100, 125, 173, 218, 291, 366, 483, 600, 784, 971, 1244, 1538, 1957, 2395, 3023, 3693, 4605, 5604, 6942, 8397, 10347, 12471, 15235, 18309, 22267, 26619, 32219, 38414, 46216, 54941, 65838, 77958, 93076, 109908
Offset: 0

Views

Author

Brian Hopkins, Feb 20 2007

Keywords

Comments

A partition of n is complete if every number 1 to n can be represented as a sum of parts of the partition. This generalizes perfect partitions, where the representation for each number must be unique.
A partition is complete iff each part is no more than 1 more than the sum of all smaller parts. (This includes the smallest part, which thus must be 1.) - Franklin T. Adams-Watters, Mar 22 2007
For n > 0: a(n) = sum of n-th row in A261036 and also a(floor(n/2)) = A261036(n,floor((n+1)/2)). - Reinhard Zumkeller, Aug 08 2015
a(n+1) is the number of partitions of n such that each part is no more than 2 more than the sum of all smaller parts (generalizing Adams-Watters's criterion). Bijection: each partition counted by a(n+1) must contain a 1, removing that gives a desired partition of n. - Brian Hopkins, May 16 2017
A partition (x_1, ..., x_k) is complete if and only if 1, x_1, ..., x_k is a "regular sequence" (see A003513 for definition). As a result, the number of complete partitions with n parts is given by A003513(n+1). - Nathaniel Johnston, Jun 29 2023

Examples

			There are a(5) = 4 complete partitions of 5:
  [1, 1, 1, 1, 1], [1, 1, 1, 2], [1, 2, 2], and [1, 1, 3].
G.f.: 1 = 1*(1-x) + 1*x*(1-x)*(1-x^2) + 1*x^2*(1-x)*(1-x^2)*(1-x^3) + 2*x^3*(1-x)*(1-x^2)*(1-x^3)*(1-x^4) + 2*x^4*(1-x)*(1-x^2)*(1-x^3)*(1-x^4)*(1-x^5) + ...
From _Gus Wiseman_, Oct 14 2023: (Start)
The a(1) = 1 through a(8) = 10 partitions:
  (1)  (11)  (21)   (211)   (221)    (321)     (421)      (3221)
             (111)  (1111)  (311)    (2211)    (2221)     (3311)
                            (2111)   (3111)    (3211)     (4211)
                            (11111)  (21111)   (4111)     (22211)
                                     (111111)  (22111)    (32111)
                                               (31111)    (41111)
                                               (211111)   (221111)
                                               (1111111)  (311111)
                                                          (2111111)
                                                          (11111111)
(End)
		

Crossrefs

For parts instead of sums we have A000009 (sc. coverings), ranks A055932.
The strict case is A188431, complement A365831.
These partitions have ranks A325781.
First column k = 0 of A365923.
The complement is counted by A365924, ranks A365830.

Programs

  • Haskell
    import Data.MemoCombinators (memo3, integral, Memo)
    a126796 n = a126796_list !! n
    a126796_list = map (pMemo 1 1) [0..] where
       pMemo = memo3 integral integral integral p
       p   0 = 1
       p s k m
         | k > min m s = 0
         | otherwise   = pMemo (s + k) k (m - k) + pMemo s (k + 1) m
    -- Reinhard Zumkeller, Aug 07 2015
  • Maple
    isCompl := proc(p,n) local m,pers,reps,f,lst,s; reps := {}; pers := combinat[permute](p); for m from 1 to nops(pers) do lst := op(m,pers); for f from 1 to nops(lst) do s := add( op(i,lst),i=1..f); reps := reps union {s}; od; od; for m from 1 to n do if not m in reps then RETURN(false); fi; od; RETURN(true); end: A126796 := proc(n) local prts, res,p; prts := combinat[partition](n); res :=0; for p from 1 to nops(prts) do if isCompl(op(p,prts),n) then res := res+1; fi; od; RETURN(res); end: for n from 1 to 40 do printf("%d %d ",n,A126796(n)); od; # R. J. Mathar, Feb 27 2007
    # At the beginning of the 2nd Maple program replace the current 15 by any other positive integer n in order to obtain a(n). - Emeric Deutsch, Mar 04 2007
    with(combinat): a:=proc(n) local P,b,k,p,S,j: P:=partition(n): b:=0: for k from 1 to numbpart(n) do p:=powerset(P[k]): S:={}: for j from 1 to nops(p) do S:=S union {add(p[j][i],i=1..nops(p[j]))} od: if nops(S)=n+1 then b:=b+1 else b:=b: fi: od: end: seq(a(n),n=1..30); # Emeric Deutsch, Mar 04 2007
    with(combinat): n:=15: P:=partition(n): b:=0: for k from 1 to numbpart(n) do p:=powerset(P[k]): S:={}: for j from 1 to nops(p) do S:=S union {add(p[j][i],i=1..nops(p[j]))} od: if nops(S)=n+1 then b:=b+1 else b:=b: fi: od: b; # Emeric Deutsch, Mar 04 2007
  • Mathematica
    T[n_, k_] := T[n, k] = If[k <= 1, 1, If[n < 2k-1, T[n, Floor[(n+1)/2]], T[n, k-1] + T[n-k, k]]];
    a[n_] := T[n, Floor[(n+1)/2]];
    Table[a[n], {n, 0, 50}] (* Jean-François Alcover, Apr 11 2017, after Franklin T. Adams-Watters *)
    nmz[y_]:=Complement[Range[Total[y]], Total/@Subsets[y]]; Table[Length[Select[IntegerPartitions[n], nmz[#]=={}&]],{n,0,15}] (* Gus Wiseman, Oct 14 2023 *)
  • PARI
    {T(n,k)=if(k<=1,1,if(n<2*k-1,T(n,floor((n+1)/2)),T(n,k-1)+T(n-k,k)))}
    {a(n)=T(n,floor((n+1)/2))} /* If modified to save earlier results, this would be efficient. */ /* Franklin T. Adams-Watters, Mar 22 2007 */
    
  • PARI
    /* As coefficients in g.f.: */
    {a(n)=local(A=[1,1]);for(i=1,n+1,A=concat(A,0);A[#A]=polcoeff(1-sum(m=1,#A,A[m]*x^m*prod(k=1,m,1-x^k +x*O(x^#A))),#A) );A[n+1]}
    for(n=0,50,print1(a(n),",")) /* Paul D. Hanna, Mar 06 2012 */
    

Formula

G.f.: 1 = Sum_{n>=0} a(n)*x^n*Product_{k=1..n+1} (1-x^k). - Paul D. Hanna, Mar 08 2012
a(n) ~ exp(Pi*sqrt(2*n/3)) / (4*sqrt(3)*n) * (1 - (sqrt(3/2)/Pi + 25*Pi/(24*sqrt(6))) / sqrt(n) + (25/16 - 1679*Pi^2/6912)/n). - Vaclav Kotesovec, May 24 2018, extended Nov 02 2019
a(n) = A000041(n) - A365924(n). - Gus Wiseman, Oct 14 2023

Extensions

More terms from R. J. Mathar, Feb 27 2007
More terms from Emeric Deutsch, Mar 04 2007
Further terms from Franklin T. Adams-Watters and David W. Wilson, Mar 22 2007

A365924 Number of incomplete 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, 3, 3, 6, 7, 12, 14, 22, 25, 38, 46, 64, 76, 106, 124, 167, 199, 261, 309, 402, 471, 604, 714, 898, 1053, 1323, 1542, 1911, 2237, 2745, 3201, 3913, 4536, 5506, 6402, 7706, 8918, 10719, 12364, 14760, 17045, 20234, 23296, 27600, 31678, 37365, 42910, 50371, 57695, 67628, 77300, 90242, 103131, 119997
Offset: 0

Views

Author

Gus Wiseman, Sep 26 2023

Keywords

Comments

The complement (complete partitions) is A126796.

Examples

			The a(0) = 0 through a(8) = 12 partitions:
  .  .  (2)  (3)  (4)    (5)    (6)      (7)      (8)
                  (2,2)  (3,2)  (3,3)    (4,3)    (4,4)
                  (3,1)  (4,1)  (4,2)    (5,2)    (5,3)
                                (5,1)    (6,1)    (6,2)
                                (2,2,2)  (3,2,2)  (7,1)
                                (4,1,1)  (3,3,1)  (3,3,2)
                                         (5,1,1)  (4,2,2)
                                                  (4,3,1)
                                                  (5,2,1)
                                                  (6,1,1)
                                                  (2,2,2,2)
                                                  (5,1,1,1)
		

Crossrefs

For parts instead of sums we have A047967/A365919, ranks A080259/A055932.
The complement is A126796, ranks A325781, strict A188431.
These partitions have ranks A365830.
The strict case is A365831.
Row sums of A365923 without the first column, strict A365545.
A000041 counts integer partitions, strict A000009.
A046663 counts partitions w/o a submultiset summing to k, strict A365663.
A276024 counts positive subset-sums of partitions, strict A284640.
A325799 counts non-subset-sums of prime indices.
A364350 counts combination-free strict partitions.
A365543 counts partitions with a submultiset summing to k, strict A365661.

Programs

  • Mathematica
    nmz[y_]:=Complement[Range[Total[y]],Total/@Subsets[y]];
    Table[Length[Select[IntegerPartitions[n],Length[nmz[#]]>0&]],{n,0,15}]

Formula

a(n) = A000041(n) - A126796(n).

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

Views

Author

Gus Wiseman, Sep 28 2023

Keywords

Examples

			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)
		

Crossrefs

For parts instead of sums we have ranks A080259, A055932.
The strict complement is A188431, non-strict A126796 (ranks A325781).
Row sums of A365545 without the first column, non-strict A365923.
The non-strict version is A365924, ranks A365830.
A000041 counts integer partitions, strict A000009.
A046663 counts partitions w/o a submultiset summing to k, strict A365663.
A276024 counts positive subset-sums of partitions, strict A284640.
A325799 counts non-subset-sums of prime indices.
A365543 counts partitions with a submultiset summing to k, strict A365661.

Programs

  • Mathematica
    nmz[y_]:=Complement[Range[Total[y]], Total/@Subsets[y]];
    Table[Length[Select[IntegerPartitions[n], UnsameQ@@#&&Length[nmz[#]]>0&]],{n,0,15}]

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

Views

Author

Gus Wiseman, Sep 26 2023

Keywords

Comments

This is the "not necessarily positive" version, cf. A284640.

Examples

			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
		

Crossrefs

The positive case is A284640.
The non-strict version is A304792, positive case A276024.
Row sums of A365661, non-strict A365543.
The complement (non-subset-sums) is A365922, non-strict A365918.
A000041 counts integer partitions, strict A000009.
A126796 counts complete partitions, ranks A325781, strict A188431.
A365923 counts partitions by non-subset-sums, strict A365545.
A365924 counts incomplete partitions, ranks A365830, strict A365831.

Programs

  • Mathematica
    Table[Total[Length[Union[Total/@Subsets[#]]]& /@ Select[IntegerPartitions[n], UnsameQ@@#&]],{n,30}]

A365830 Heinz numbers of incomplete integer partitions, meaning not every number from 0 to A056239(n) is the sum of some submultiset.

Original entry on oeis.org

3, 5, 7, 9, 10, 11, 13, 14, 15, 17, 19, 21, 22, 23, 25, 26, 27, 28, 29, 31, 33, 34, 35, 37, 38, 39, 41, 43, 44, 45, 46, 47, 49, 50, 51, 52, 53, 55, 57, 58, 59, 61, 62, 63, 65, 66, 67, 68, 69, 70, 71, 73, 74, 75, 76, 77, 78, 79, 81, 82, 83, 85, 86, 87, 88, 89
Offset: 1

Views

Author

Gus Wiseman, Sep 26 2023

Keywords

Comments

First differs from A325798 in lacking 156.
The Heinz number of a partition (y_1,...,y_k) is prime(y_1)*...*prime(y_k). This gives a bijective correspondence between positive integers and integer partitions.
The complement (complete partitions) is A325781.

Examples

			The terms together with their prime indices begin:
   3: {2}
   5: {3}
   7: {4}
   9: {2,2}
  10: {1,3}
  11: {5}
  13: {6}
  14: {1,4}
  15: {2,3}
  17: {7}
  19: {8}
  21: {2,4}
  22: {1,5}
  23: {9}
  25: {3,3}
  26: {1,6}
  27: {2,2,2}
  28: {1,1,4}
For example, the submultisets of (1,1,2,6) (right column) and their sums (left column) are:
   0: ()
   1: (1)
   2: (2)  or (11)
   3: (12)
   4: (112)
   6: (6)
   7: (16)
   8: (26) or (116)
   9: (126)
  10: (1126)
But 5 is missing, so 156 is in the sequence.
		

Crossrefs

For prime indices instead of sums we have A080259, complement of A055932.
The complement is A325781, counted by A126796, strict A188431.
Positions of nonzero terms in A325799, complement A304793.
These partitions are counted by A365924, strict A365831.
A056239 adds up prime indices, row sums of A112798.
A276024 counts positive subset-sums of partitions, strict A284640
A299701 counts distinct subset-sums of prime indices.
A365918 counts distinct non-subset-sums of partitions, strict A365922.
A365923 counts partitions by distinct non-subset-sums, strict A365545.

Programs

  • Mathematica
    prix[n_]:=If[n==1,{},Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]];
    nmz[y_]:=Complement[Range[Total[y]],Total/@Subsets[y]];
    Select[Range[100],Length[nmz[prix[#]]]>0&]

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

Views

Author

Gus Wiseman, Sep 23 2023

Keywords

Comments

For an integer partition y of n, we call a positive integer k <= n a non-subset-sum iff there is no submultiset of y summing to k.

Examples

			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):
		

Crossrefs

Row sums of A046663, strict A365663.
The zero-full complement (subset-sums) is A304792.
The strict case is A365922.
Weighted row-sums of A365923, rank statistic A325799, complement A365658.
A000041 counts integer partitions, strict A000009.
A126796 counts complete partitions, ranks A325781, strict A188431.
A365543 counts partitions with a submultiset summing to k, strict A365661.
A365924 counts incomplete partitions, ranks A365830, strict A365831.

Programs

  • Mathematica
    Table[Total[Length[Complement[Range[n],Total/@Subsets[#]]]&/@IntegerPartitions[n]],{n,10}]
  • Python
    # 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

Formula

a(n) = (n+1)*A000041(n) - A304792(n).

Extensions

a(21)-a(45) from Chai Wah Wu, Sep 25 2023

A366754 Number of non-knapsack integer partitions of n.

Original entry on oeis.org

0, 0, 0, 0, 1, 1, 4, 4, 10, 13, 23, 27, 52, 60, 94, 118, 175, 213, 310, 373, 528, 643, 862, 1044, 1403, 1699, 2199, 2676, 3426, 4131, 5256, 6295, 7884, 9479, 11722, 14047, 17296, 20623, 25142, 29942, 36299, 43081, 51950, 61439, 73668, 87040, 103748, 122149, 145155, 170487
Offset: 0

Views

Author

Gus Wiseman, Nov 08 2023

Keywords

Comments

A multiset is non-knapsack if there exist two different submultisets with the same sum.

Examples

			The a(4) = 1 through a(9) = 13 partitions:
  (211)  (2111)  (321)    (3211)    (422)      (3321)
                 (2211)   (22111)   (431)      (4221)
                 (3111)   (31111)   (3221)     (4311)
                 (21111)  (211111)  (4211)     (5211)
                                    (22211)    (32211)
                                    (32111)    (33111)
                                    (41111)    (42111)
                                    (221111)   (222111)
                                    (311111)   (321111)
                                    (2111111)  (411111)
                                               (2211111)
                                               (3111111)
                                               (21111111)
		

Crossrefs

The complement is counted by A108917, strict A275972, ranks A299702.
These partitions have ranks A299729.
The strict case is A316402.
The binary version is A366753, ranks A366740.
A000041 counts integer partitions, strict A000009.
A276024 counts positive subset-sums of partitions, strict A284640.
A304792 counts subset-sum of partitions, strict A365925.
A365543 counts partitions with subset-sum k, complement A046663.
A365661 counts strict partitions with subset-sum k, complement A365663.
A366738 counts semi-sums of partitions, strict A366741.

Programs

  • Mathematica
    Table[Length[Select[IntegerPartitions[n], !UnsameQ@@Total/@Union[Subsets[#]]&]], {n,0,15}]

Formula

a(n) = A000041(n) - A108917(n).

A365545 Triangle read by rows where T(n,k) is the number of strict integer partitions of n with exactly k distinct non-subset-sums.

Original entry on oeis.org

1, 1, 0, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 0, 0, 2, 0, 1, 0, 1, 0, 0, 2, 0, 1, 0, 1, 0, 0, 0, 3, 0, 1, 0, 0, 1, 1, 0, 0, 3, 0, 1, 0, 0, 0, 3, 0, 0, 0, 4, 0, 1, 0, 1, 0, 0, 2, 2, 0, 0, 4, 0, 1, 0, 1, 0, 0, 0, 5, 0, 0, 0, 5, 0, 1, 0, 2, 0, 0, 0, 0, 5, 2, 0, 0, 5, 0, 1, 0
Offset: 0

Views

Author

Gus Wiseman, Sep 24 2023

Keywords

Comments

For an integer partition y of n, we call a positive integer k <= n a non-subset-sum iff there is no submultiset of y summing to k.
Is column k = n - 7 given by A325695?

Examples

			Triangle begins:
  1
  1  0
  0  1  0
  1  0  1  0
  0  1  0  1  0
  0  0  2  0  1  0
  1  0  0  2  0  1  0
  1  0  0  0  3  0  1  0
  0  1  1  0  0  3  0  1  0
  0  0  3  0  0  0  4  0  1  0
  1  0  0  2  2  0  0  4  0  1  0
  1  0  0  0  5  0  0  0  5  0  1  0
  2  0  0  0  0  5  2  0  0  5  0  1  0
  2  0  1  0  0  0  8  0  0  0  6  0  1  0
  1  1  3  0  0  0  0  7  3  0  0  6  0  1  0
  2  0  4  0  1  0  0  0 12  0  0  0  7  0  1  0
  1  1  2  2  3  1  0  0  0 11  3  0  0  7  0  1  0
  2  0  3  0  7  0  1  0  0  0 16  0  0  0  8  0  1  0
  3  0  0  2  6  3  3  1  0  0  0 15  4  0  0  8  0  1  0
Row n = 12: counts the following partitions:
  (6,3,2,1)  .  .  .  .  (9,2,1)  (6,5,1)  .  .  (11,1)  .  (12)  .
  (5,4,2,1)              (8,3,1)  (6,4,2)        (10,2)
                         (7,4,1)                 (9,3)
                         (7,3,2)                 (8,4)
                         (5,4,3)                 (7,5)
		

Crossrefs

Row sums are A000009, non-strict A000041.
The complement (positive subset-sums) is also A365545 with rows reversed.
Weighted row sums are A365922, non-strict A365918.
The non-strict version is A365923, complement A365658, rank stat A325799.
A046663 counts partitions without a subset summing to k, strict A365663.
A126796 counts complete partitions, ranks A325781, strict A188431.
A364350 counts combination-free strict partitions, complement A364839.
A365543 counts partitions with a submultiset summing to k, strict A365661.
A365924 counts incomplete partitions, ranks A365830, strict A365831.

Programs

  • Mathematica
    Table[Length[Select[IntegerPartitions[n], UnsameQ@@#&&Length[Complement[Range[n], Total/@Subsets[#]]]==k&]],{n,0,10},{k,0,n}]

A365922 Number of non-subset-sums of strict integer partitions of n.

Original entry on oeis.org

0, 1, 2, 4, 8, 11, 18, 25, 38, 51, 70, 93, 122, 159, 206, 263, 328, 420, 514, 645, 776, 967, 1154, 1413, 1686, 2042, 2414, 2890, 3394, 4062, 4732, 5598, 6494, 7652, 8836, 10329, 11884, 13833, 15830, 18376, 20936, 24131, 27476, 31547, 35780, 40966, 46292, 52737
Offset: 1

Views

Author

Gus Wiseman, Sep 23 2023

Keywords

Comments

For an integer partition y of n, we call a positive integer k <= n a non-subset-sum iff there is no submultiset of y summing to k.

Examples

			The a(6) = 11 ways, showing each strict partition and its non-subset-sums:
    (6): 1,2,3,4,5
   (51): 2,3,4
   (42): 1,3,5
  (321):
		

Crossrefs

The complement (positive subset-sums) is A284640, non-strict A276024.
Weighted row sums of A365545, non-strict A365923.
Row sums of A365663, non-strict A046663.
The non-strict version is A365918.
The zero-full complement (subset-sums) is A365925, non-strict A304792.
A000041 counts integer partitions, strict A000009.
A126796 counts complete partitions, ranks A325781, strict A188431.
A364350 counts combination-free strict partitions, complement A364839.
A365543 counts partitions with a submultiset summing to k.
A365661 counts strict partitions w/ a subset summing to k.
A365924 counts incomplete partitions, ranks A365830, strict A365831.

Programs

  • Mathematica
    Table[Total[Length[Complement[Range[n], Total/@Subsets[#]]]& /@ Select[IntegerPartitions[n], UnsameQ@@#&]],{n,30}]

A366753 Number of integer partitions of n without all different sums of two-element submultisets.

Original entry on oeis.org

0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 3, 4, 9, 11, 22, 27, 48, 61, 98, 123, 188, 237, 345, 435, 611, 765, 1046, 1305, 1741, 2165, 2840, 3502, 4527, 5562, 7083, 8650, 10908, 13255, 16545, 20016, 24763, 29834, 36587, 43911, 53514, 63964, 77445, 92239, 111015, 131753
Offset: 0

Views

Author

Gus Wiseman, Nov 07 2023

Keywords

Examples

			The two-element submultisets of y = {1,1,1,2,2,3} are {1,1}, {1,2}, {1,3}, {2,2}, {2,3}, with sums 2, 3, 4, 4, 5, which are not all different, so y is counted under a(10).
The a(8) = 1 through a(13) = 11 partitions:
  (3221)  (32211)  (4321)    (33221)    (4332)      (43321)
                   (32221)   (43211)    (5331)      (53221)
                   (322111)  (322211)   (5421)      (53311)
                             (3221111)  (43221)     (54211)
                                        (322221)    (332221)
                                        (332211)    (432211)
                                        (432111)    (3222211)
                                        (3222111)   (3322111)
                                        (32211111)  (4321111)
                                                    (32221111)
                                                    (322111111)
		

Crossrefs

Semiprime divisors are counted by A086971, distinct sums A366739.
The non-binary complement is A108917, strict A275972, ranks A299702.
These partitions have ranks A366740.
The non-binary version is A366754, strict A316402, ranks A299729.
A276024 counts positive subset-sums of partitions, strict A284640.
A304792 counts subset-sum of partitions, strict A365925.
A365543 counts partitions with a subset-sum k, complement A046663.
A365661 counts strict partitions with a subset-sum k, complement A365663.
A366738 counts semi-sums of partitions, strict A366741.
A367096 lists semiprime divisors, row sums A076290.

Programs

  • Mathematica
    Table[Length[Select[IntegerPartitions[n],!UnsameQ@@Total/@Union[Subsets[#,{2}]]&]],{n,0,30}]
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