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.

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A340607 Number of factorizations of n into an odd number of factors > 1, the greatest of which is odd.

Original entry on oeis.org

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

Views

Author

Gus Wiseman, Jan 25 2021

Keywords

Examples

			The a(n) factorizations for n = 27, 84, 108, 180, 252, 360, 432:
  27     2*6*7   2*6*9      4*5*9      4*7*9      5*8*9       6*8*9
  3*3*3  3*4*7   3*4*9      2*2*45     6*6*7      2*4*45      2*8*27
         2*2*21  2*2*27     2*6*15     2*2*63     3*8*15      4*4*27
                 2*2*3*3*3  3*4*15     2*6*21     4*6*15      2*2*2*6*9
                            2*2*3*3*5  3*4*21     2*12*15     2*2*3*4*9
                                       2*2*3*3*7  2*2*2*5*9   2*2*2*2*27
                                                  2*3*3*4*5   2*2*2*2*3*3*3
                                                  2*2*2*3*15
		

Crossrefs

Note: Heinz numbers are given in parentheses below.
The case of odd length only is A339890.
The case of all odd factors is A340102.
The version for partitions is A340385.
The version for prime indices is A340386.
The case of odd maximum only is A340831.
A000009 counts partitions into odd parts (A066208).
A001055 counts factorizations, with strict case A045778.
A027193 counts partitions of odd length/maximum (A026424/A244991).
A058695 counts partitions of odd numbers (A300063).
A078408 counts odd-length partitions into odd numbers (A300272).
A316439 counts factorizations by sum and length.
A340101 counts factorizations (into odd factors = of odd numbers).
A340832 counts factorizations whose least part is odd.
A340854/A340855 lack/have a factorization with odd minimum.

Programs

  • Mathematica
    facs[n_]:=If[n<=1,{{}},Join@@Table[Map[Prepend[#,d]&,Select[facs[n/d],Min@@#>=d&]],{d,Rest[Divisors[n]]}]];
    Table[Length[Select[facs[n],OddQ[Length[#]]&&OddQ[Max@@#]&]],{n,100}]
  • PARI
    A340607(n, m=n, k=0, grodd=0) = if(1==n, k, my(s=0); fordiv(n, d, if((d>1)&&(d<=m)&&(grodd||(d%2)), s += A340607(n/d, d, 1-k, bitor(1,grodd)))); (s)); \\ Antti Karttunen, Dec 13 2021

Extensions

Data section extended up to 108 terms by Antti Karttunen, Dec 13 2021

A340385 Number of integer partitions of n into an odd number of parts, the greatest of which is odd.

Original entry on oeis.org

1, 0, 2, 0, 3, 1, 6, 3, 10, 7, 18, 15, 30, 28, 51, 50, 82, 87, 134, 145, 211, 235, 331, 375, 510, 586, 779, 901, 1172, 1366, 1750, 2045, 2581, 3026, 3778, 4433, 5476, 6430, 7878, 9246, 11240, 13189, 15931, 18670, 22417, 26242, 31349, 36646, 43567, 50854
Offset: 1

Views

Author

Gus Wiseman, Jan 08 2021

Keywords

Examples

			The a(3) = 2 through a(10) = 7 partitions:
  3     5       321   7         332     9           532
  111   311           322       521     333         541
        11111         331       32111   522         721
                      511               531         32221
                      31111             711         33211
                      1111111           32211       52111
                                        33111       3211111
                                        51111
                                        3111111
                                        111111111
		

Crossrefs

Partitions of odd length are counted by A027193, ranked by A026424.
Partitions with odd maximum are counted by A027193, ranked by A244991.
The Heinz numbers of these partitions are given by A340386.
Other cases of odd length:
- A024429 counts set partitions of odd length.
- A067659 counts strict partitions of odd length.
- A089677 counts ordered set partitions of odd length.
- A166444 counts compositions of odd length.
- A174726 counts ordered factorizations of odd length.
- A332304 counts strict compositions of odd length.
- A339890 counts factorizations of odd length.
A000009 counts partitions into odd parts, ranked by A066208.
A026804 counts partitions whose least part is odd.
A058695 counts partitions of odd numbers, ranked by A300063.
A072233 counts partitions by sum and length.
A101707 counts partitions with odd rank.
A160786 counts odd-length partitions of odd numbers, ranked by A300272.
A340101 counts factorizations into odd factors.
A340102 counts odd-length factorizations into odd factors.

Programs

  • Mathematica
    Table[Length[Select[IntegerPartitions[n],OddQ[Length[#]*Max[#]]&]],{n,30}]

A340386 Heinz numbers of integer partitions with an odd number of parts, the greatest of which is odd.

Original entry on oeis.org

2, 5, 8, 11, 17, 20, 23, 30, 31, 32, 41, 44, 45, 47, 50, 59, 66, 67, 68, 73, 75, 80, 83, 92, 97, 99, 102, 103, 109, 110, 120, 124, 125, 127, 128, 137, 138, 149, 153, 154, 157, 164, 165, 167, 170, 176, 179, 180, 186, 188, 191, 197, 200, 207, 211, 227, 230
Offset: 1

Views

Author

Gus Wiseman, Jan 25 2021

Keywords

Comments

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.

Examples

			The sequence of partitions together with their Heinz numbers begins:
      2: (1)             59: (17)           120: (3,2,1,1,1)
      5: (3)             66: (5,2,1)        124: (11,1,1)
      8: (1,1,1)         67: (19)           125: (3,3,3)
     11: (5)             68: (7,1,1)        127: (31)
     17: (7)             73: (21)           128: (1,1,1,1,1,1,1)
     20: (3,1,1)         75: (3,3,2)        137: (33)
     23: (9)             80: (3,1,1,1,1)    138: (9,2,1)
     30: (3,2,1)         83: (23)           149: (35)
     31: (11)            92: (9,1,1)        153: (7,2,2)
     32: (1,1,1,1,1)     97: (25)           154: (5,4,1)
     41: (13)            99: (5,2,2)        157: (37)
     44: (5,1,1)        102: (7,2,1)        164: (13,1,1)
     45: (3,2,2)        103: (27)           165: (5,3,2)
     47: (15)           109: (29)           167: (39)
     50: (3,3,1)        110: (5,3,1)        170: (7,3,1)
		

Crossrefs

Note: Heinz numbers are given in parentheses below.
The case of odd length only is A026424.
The case of odd maximum only is A244991.
Positions of odd terms in A326846.
These partitions are counted by A340385.
The version for factorizations is A340607.
A000009 counts partitions into odd parts (A066208).
A027193 counts partitions of odd length, or of odd maximum.
A061395 gives maximum prime index.
A106529 lists numbers with Omega equal to maximum prime index.
A160786 counts odd-length partitions of odd numbers (A300272).
A339890 counts factorizations of odd length.
A340102 counts odd-length factorizations into odd factors.

Programs

  • Mathematica
    Select[Range[100],OddQ[PrimeOmega[#]*PrimePi[FactorInteger[#][[-1,1]]]]&]

Formula

Intersection of A026424 (odd length) and A244991 (odd maximum).

A350951 Number of odd parts minus number of odd conjugate parts in the integer partition with Heinz number n.

Original entry on oeis.org

0, 0, -2, 2, -2, 0, -4, 2, 0, 0, -4, 0, -6, -2, 0, 4, -6, 0, -8, 0, -2, -2, -8, 2, 2, -4, -2, -2, -10, 0, -10, 4, -2, -4, 0, 2, -12, -6, -4, 2, -12, -2, -14, -2, -2, -6, -14, 2, 0, 2, -4, -4, -16, 0, 0, 0, -6, -8, -16, 2, -18, -8, -4, 6, -2, -2, -18, -4, -6, 0
Offset: 1

Views

Author

Gus Wiseman, Mar 14 2022

Keywords

Comments

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.
All terms are even.

Examples

			The prime indices of 78 are (6,2,1), with conjugate (3,2,1,1,1,1), so a(78) = 1 - 5 = -4.
		

Crossrefs

The version comparing even with odd parts is A195017.
The version comparing even with odd conjugate parts is A350849.
The version comparing even conjugate with odd conjugate parts is A350941.
The version comparing odd with even conjugate parts is A350942.
Positions of 0's are A350944, even rank case A345196, counted by A277103.
The version comparing even with even conjugate parts is A350950.
There are four individual statistics:
- A257991 counts odd parts, conjugate A344616.
- A257992 counts even parts, conjugate A350847.
There are five other possible pairings of statistics:
- A325698: # of even parts = # of odd parts, counted by A045931.
- A349157: # of even parts = # of odd conjugate parts, counted by A277579.
- A350848: # of even conj parts = # of odd conj parts, counted by A045931.
- A350943: # of even conjugate parts = # of odd parts, counted by A277579.
- A350945: # of even parts = # of even conjugate parts, counted by A350948.
There are three possible double-pairings of statistics:
- A350946, counted by A351977.
- A350949, counted by A351976.
- A351980, counted by A351981.
The case of all four statistics equal is A350947, counted by A351978.
A056239 adds up prime indices, counted by A001222, row sums of A112798.
A103919 counts partitions by number of odd parts.
A116482 counts partitions by number of even parts.
A122111 represents partition conjugation using Heinz numbers.
A316524 gives the alternating sum of prime indices.

Programs

  • Mathematica
    primeMS[n_]:=If[n==1,{},Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]];
    conj[y_]:=If[Length[y]==0,y,Table[Length[Select[y,#>=k&]],{k,1,Max[y]}]];
    Table[Count[primeMS[n],?OddQ]-Count[conj[primeMS[n]],?OddQ],{n,100}]

Formula

a(n) = A257991 - A344616(n).
a(A122111(n)) = -a(n), where A122111 represents partition conjugation.

A351976 Number of integer partitions of n with (1) as many odd parts as odd conjugate parts and (2) as many even parts as even conjugate parts.

Original entry on oeis.org

1, 1, 0, 1, 1, 1, 1, 1, 2, 2, 2, 4, 5, 5, 5, 6, 9, 11, 11, 16, 21, 22, 24, 31, 41, 46, 48, 64, 82, 91, 98, 120, 155, 175, 188, 237, 297, 329, 357, 437, 544, 607, 658, 803, 987, 1098, 1196, 1432, 1749, 1955, 2126, 2541, 3071, 3417, 3729, 4406, 5291, 5890, 6426
Offset: 0

Views

Author

Gus Wiseman, Mar 14 2022

Keywords

Examples

			The a(n) partitions for selected n:
n = 3     8       11        12        15          16
   ----------------------------------------------------------
    (21)  (332)   (4322)    (4332)    (4443)      (4444)
          (4211)  (4331)    (4422)    (54321)     (53332)
                  (4421)    (4431)    (632211)    (55222)
                  (611111)  (53211)   (633111)    (55411)
                            (621111)  (642111)    (633211)
                                      (81111111)  (642211)
                                                  (643111)
                                                  (7321111)
                                                  (82111111)
		

Crossrefs

The first condition alone is A277103, ranked by A350944, strict A000700.
The second condition alone is A350948, ranked by A350945.
These partitions are ranked by A350949.
A000041 counts integer partitions.
A122111 represents partition conjugation using Heinz numbers.
A195017 = # of even parts - # of odd parts.
There are four statistics:
- A257991 = # of odd parts, conjugate A344616.
- A257992 = # of even parts, conjugate A350847.
There are four other possible pairings of statistics:
- A045931: # even = # odd, ranked by A325698, strict A239241.
- A045931: # even conj = # odd conj, ranked by A350848, strict A352129.
- A277579: # even = # odd conj, ranked by A349157, strict A352131.
- A277579: # even conj = # odd, ranked by A350943, strict A352130.
There are two other possible double-pairings of statistics:
- A351977: # even = # odd, # even conj = # odd conj, ranked by A350946.
- A351981: # even = # odd conj, # odd = # even conj, ranked by A351980.
The case of all four statistics equal is A351978, ranked by A350947.

Programs

A351977 Number of integer partitions of n with as many even parts as odd parts and as many even conjugate parts as odd conjugate parts.

Original entry on oeis.org

1, 0, 0, 1, 0, 0, 0, 0, 1, 2, 1, 0, 2, 0, 2, 4, 2, 1, 6, 6, 7, 9, 11, 10, 13, 17, 17, 21, 28, 36, 35, 41, 58, 71, 72, 90, 106, 121, 142, 178, 191, 216, 269, 320, 344, 400, 486, 564, 633, 734, 867, 991, 1130, 1312, 1509, 1702, 1978, 2288, 2582, 2917, 3404
Offset: 0

Views

Author

Gus Wiseman, Mar 14 2022

Keywords

Examples

			The a(n) partitions for selected n (A..C = 10..12):
n = 3     9         15            18          20
   ----------------------------------------------------------
    (21)  (63)      (A5)          (8433)      (8543)
          (222111)  (632211)      (8532)      (8741)
                    (642111)      (8631)      (C611)
                    (2222211111)  (43322211)  (43332221)
                                  (44322111)  (44432111)
                                  (44421111)  (84221111)
                                              (422222111111)
		

Crossrefs

The first condition alone is A045931, ranked by A325698, strict A239241.
The second condition alone is A045931, ranked by A350848, strict A352129.
These partitions are ranked by A350946.
The strict case is A352128.
There are four statistics:
- A257991 = # of odd parts, conjugate A344616.
- A257992 = # of even parts, conjugate A350847.
There are four additional pairings of statistics:
- A277579: # even = # odd conj, ranked by A349157, strict A352131.
- A277579: # even conj = # odd, ranked by A350943, strict A352130.
- A277103: # odd = # odd conj, ranked by A350944, strict A000700.
- A350948: # even = # even conj, ranked by A350945.
There are two additional double-pairings of statistics:
- A351981, ranked by A351980.
- A351976, ranked by A350949.
The case of all four statistics equal is A351978, ranked by A350947.

Programs

  • Mathematica
    conj[y_]:=If[Length[y]==0,y,Table[Length[Select[y,#>=k&]],{k,1,Max[y]}]];
    Table[Length[Select[IntegerPartitions[n],Count[#,?OddQ]==Count[#,?EvenQ]&&Count[conj[#],?OddQ]==Count[conj[#],?EvenQ]&]],{n,0,30}]

A351978 Number of integer partitions of n for which the number of even parts, the number of odd parts, the number of even conjugate parts, and the number of odd conjugate parts are all equal.

Original entry on oeis.org

1, 0, 0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 2, 0, 0, 2, 0, 1, 0, 6, 1, 3, 1, 8, 5, 3, 5, 7, 14, 2, 13, 9, 28, 5, 22, 26, 44, 17, 30, 60, 59, 42, 41, 120, 84, 84, 66, 204, 143, 144, 131, 325, 268, 226, 261, 486, 498, 344, 488, 739, 874
Offset: 0

Views

Author

Gus Wiseman, Mar 15 2022

Keywords

Examples

			The a(n) partitions for selected n (A = 10):
n = 3    12     19       21       23       24         27
   --------------------------------------------------------------
    21   4332   633322   643332   644333   84332211   655443
         4431   643321   654321   654332   84441111   655542
                644311   665211   654431   85322211   665541
                653221            655322   86322111   666333
                654211            655421   86421111   666531
                664111            664331              A522221111
                                  665321              A622211111
                                  666311
		

Crossrefs

The strict case appears to be the indicator function for A014105.
These partitions are ranked by A350947.
There are four statistics:
- A257991 = # of odd parts, conjugate A344616.
- A257992 = # of even parts, conjugate A350847.
There are six pairings of statistics:
- A045931: # of even parts = # of odd parts:
- ordered A098123
- strict A239241
- ranked by A325698
- A045931: # even conj = # odd conj, ranked by A350848, strict A352129.
- A277579: # even = # odd conj, ranked by A349157, strict A352131.
- A277103: # odd = # odd conj, ranked by A350944, strict A000700.
- A277579: # even conj = # odd, ranked by A350943, strict A352130.
- A350948: # even = # even conj, ranked by A350945.
There are three double-pairings of statistics:
- A351976, ranked by A350949.
- A351977, ranked by A350946.
- A351981, ranked by A351980.
A000041 counts integer partitions, strict A000009.
A103919 and A116482 count partitions by sum and number of odd/even parts.
A195017 = # of even parts - # of odd parts.

Programs

  • Mathematica
    conj[y_]:=If[Length[y]==0,y,Table[Length[Select[y,#>=k&]],{k,1,Max[y]}]];
    Table[Length[Select[IntegerPartitions[n],Count[#,?EvenQ]==Count[#,?OddQ]==Count[conj[#],?EvenQ]==Count[conj[#],?OddQ]&]],{n,0,30}]

A351981 Number of integer partitions of n with as many even parts as odd conjugate parts, and as many odd parts as even conjugate parts.

Original entry on oeis.org

1, 0, 0, 1, 0, 0, 0, 0, 1, 2, 1, 0, 2, 2, 2, 4, 2, 1, 6, 8, 7, 9, 13, 14, 15, 19, 21, 23, 32, 40, 41, 45, 66, 81, 80, 96, 124, 139, 160, 194, 221, 246, 303, 360, 390, 446, 546, 634, 703, 810, 971, 1115, 1250, 1448, 1685, 1910
Offset: 0

Views

Author

Gus Wiseman, Mar 15 2022

Keywords

Examples

			The a(n) partitions for selected n:
n = 3    9      15       18       19       20         21
   -----------------------------------------------------------
    21   4221   622221   633222   633322   644321     643332
         4311   632211   643221   643321   653321     654321
                642111   643311   644221   654221     665211
                651111   644211   644311   654311     82222221
                         653211   653221   82222211   83222211
                         663111   653311   84221111   84222111
                                  654211   86111111   85221111
                                  664111              86211111
                                                      87111111
For example, the partition (6,6,3,1,1,1) has conjugate (6,3,3,2,2,2), and has 2 even, 4 odd, 4 even conjugate, and 2 odd conjugate parts, so is counted under a(18).
		

Crossrefs

The first condition alone is A277579, ranked by A349157.
The second condition alone is A277579, ranked by A350943.
These partitions are ranked by A351980.
There are four statistics:
- A257991 = # of odd parts, conjugate A344616.
- A257992 = # of even parts, conjugate A350847.
There are four other pairings of statistics:
- A045931: # of even parts = # of odd parts:
- conjugate also A045931
- ordered A098123
- strict A239241
- ranked by A325698
- conjugate ranked by A350848
- A277103: # of odd parts = # of odd conjugate parts, ranked by A350944.
- A350948: # of even parts = # of even conjugate parts, ranked by A350945.
There are two other double-pairings of statistics:
- A351976, ranked by A350949.
- A351977, ranked by A350946.
The case of all four statistics equal is A351978, ranked by A350947.

Programs

A347444 Number of odd-length integer partitions of n with integer alternating product.

Original entry on oeis.org

0, 1, 1, 2, 2, 4, 4, 8, 7, 14, 13, 24, 21, 40, 35, 62, 55, 99, 85, 151, 128, 224, 195, 331, 283, 481, 416, 690, 593, 980, 844, 1379, 1189, 1918, 1665, 2643, 2292, 3630, 3161, 4920, 4299, 6659, 5833, 8931, 7851, 11905, 10526, 15805, 13987, 20872, 18560, 27398
Offset: 0

Views

Author

Gus Wiseman, Sep 14 2021

Keywords

Comments

We define the alternating product of a sequence (y_1, ... ,y_k) to be the Product_i y_i^((-1)^(i-1)).
The reverse version (integer reverse-alternating product) is the same.

Examples

			The a(1) = 1 through a(9) = 14 partitions:
  (1)  (2)  (3)    (4)    (5)      (6)      (7)        (8)        (9)
            (111)  (211)  (221)    (222)    (322)      (332)      (333)
                          (311)    (411)    (331)      (422)      (441)
                          (11111)  (21111)  (421)      (611)      (522)
                                            (511)      (22211)    (621)
                                            (22111)    (41111)    (711)
                                            (31111)    (2111111)  (22221)
                                            (1111111)             (32211)
                                                                  (33111)
                                                                  (42111)
                                                                  (51111)
                                                                  (2211111)
                                                                  (3111111)
                                                                  (111111111)
		

Crossrefs

The reciprocal version is A035363.
Allowing any alternating product gives A027193.
The multiplicative version (factorizations) is A347441.
Allowing any length gives A347446, reverse A347445.
Allowing any length and alternating product > 1 gives A347448.
Allowing any reverse-alternating product > 1 gives A347449.
Ranked by A347453.
The even-length instead of odd-length version is A347704.
A000041 counts partitions.
A000302 counts odd-length compositions, ranked by A053738.
A025047 counts wiggly compositions.
A026424 lists numbers with odd bigomega.
A027187 counts partitions of even length, strict A067661.
A103919 counts partitions by sum and alternating sum (reverse: A344612).
A119620 counts partitions with alternating product 1, ranked by A028982.
A325534 counts separable partitions, ranked by A335433.
A325535 counts inseparable partitions, ranked by A335448.
A339890 counts odd-length factorizations.
A347437 counts factorizations with integer alternating product.
A347461 counts possible alternating products of partitions.

Programs

  • Mathematica
    altprod[q_]:=Product[q[[i]]^(-1)^(i-1),{i,Length[q]}];
    Table[Length[Select[IntegerPartitions[n],OddQ[Length[#]]&&IntegerQ[altprod[#]]&]],{n,0,30}]

A344743 Number of integer partitions of 2n with reverse-alternating sum < 0.

Original entry on oeis.org

0, 0, 1, 3, 7, 15, 29, 54, 96, 165, 275, 449, 716, 1123, 1732, 2635, 3955, 5871, 8620, 12536, 18065, 25821, 36617, 51560, 72105, 100204, 138417, 190134, 259772, 353134, 477734, 643354, 862604, 1151773, 1531738, 2029305, 2678650, 3523378, 4618835, 6035240, 7861292
Offset: 0

Views

Author

Gus Wiseman, Jun 09 2021

Keywords

Comments

Conjecture: a(n) >= A236914.
The reverse-alternating sum of a partition (y_1,...,y_k) is Sum_i (-1)^(k-i) y_i. This is equal to (-1)^(m-1) times the number of odd parts in the conjugate partition, where m is the number of parts. So a(n) is the number of even-length partitions of 2n with at least one odd conjugate part. By conjugation, this is also the number of partitions of 2n with greatest part even and at least one odd part.
The alternating sum of a partition is never < 0, so the non-reverse version is A000004.

Examples

			The a(2) = 1 through a(5) = 15 partitions:
  (31)  (42)    (53)      (64)
        (51)    (62)      (73)
        (3111)  (71)      (82)
                (3221)    (91)
                (4211)    (3331)
                (5111)    (4222)
                (311111)  (4321)
                          (5221)
                          (5311)
                          (6211)
                          (7111)
                          (322111)
                          (421111)
                          (511111)
                          (31111111)
		

Crossrefs

The ordered version (compositions not partitions) appears to be A008549.
The Heinz numbers are A119899 /\ A300061.
Even bisection of A344608.
The complementary partitions of 2n are counted by A344611.
A000041 counts partitions of 2n with alternating sum 0, ranked by A000290.
A001523 counts unimodal compositions (partial sums: A174439).
A103919 counts partitions by sum and alternating sum (reverse: A344612).
A120452 counts partitions of 2n with rev-alt sum 2 (negative: A344741).
A124754 gives alternating sums of standard compositions (reverse: A344618).
A316524 is the alternating sum of the prime indices of n (reverse: A344616).
A325534/A325535 count separable/inseparable partitions.
A344610 counts partitions by sum and positive reverse-alternating sum.

Programs

  • Mathematica
    sats[y_] := Sum[(-1)^(i - Length[y])*y[[i]], {i, Length[y]}];
    Table[Length[Select[IntegerPartitions[n],sats[#]<0&]],{n,0,30,2}]

Formula

a(n) = A058696(n) - A344611(n).
a(n) = sum of left half of even-indexed rows of A344612.

Extensions

More terms from Bert Dobbelaere, Jun 12 2021
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