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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A343342 Number of integer partitions of n with no part dividing or divisible by all the others.

Original entry on oeis.org

1, 0, 0, 0, 0, 1, 0, 3, 2, 5, 5, 12, 7, 22, 20, 32, 34, 60, 54, 98, 93, 145, 159, 237, 229, 361, 384, 529, 574, 810, 840, 1194, 1275, 1703, 1886, 2484, 2660, 3566, 3909, 4987, 5520, 7092, 7737, 9907, 10917, 13603, 15226, 18910, 20801, 25912, 28797
Offset: 0

Views

Author

Gus Wiseman, Apr 15 2021

Keywords

Comments

Alternative name: Number of integer partitions of n that are either empty or have smallest part not dividing all the others and greatest part not divisible by all the others.

Examples

			The a(0) = 1 through a(12) = 7 partitions (empty columns indicated by dots):
  ()  .  .  .  .  (32)  .  (43)   (53)   (54)    (64)    (65)     (75)
                           (52)   (332)  (72)    (73)    (74)     (543)
                           (322)         (432)   (433)   (83)     (552)
                                         (522)   (532)   (92)     (732)
                                         (3222)  (3322)  (443)    (4332)
                                                         (533)    (5322)
                                                         (542)    (33222)
                                                         (722)
                                                         (3332)
                                                         (4322)
                                                         (5222)
                                                         (32222)
		

Crossrefs

The opposite version is A130714.
The first condition alone gives A338470.
The Heinz numbers of these partitions are A343338 = A342193 /\ A343337.
The second condition alone gives A343341.
The half-opposite versions are A343344 and A343345.
The "or" instead of "and" version is A343346 (strict: A343382).
The strict case is A343379.
A000009 counts strict partitions.
A000041 counts partitions.
A000070 counts partitions with a selected part (strict: A015723).

Programs

  • Mathematica
    Table[Length[Select[IntegerPartitions[n],#=={}||!And@@IntegerQ/@(#/Min@@#)&&!And@@IntegerQ/@(Max@@#/#)&]],{n,0,30}]

A343346 Number of integer partitions of n that are empty, have smallest part not dividing all the others, or greatest part not divisible by all the others.

Original entry on oeis.org

1, 0, 0, 0, 0, 1, 1, 4, 6, 11, 16, 29, 36, 59, 80, 112, 150, 214, 271, 374, 476, 624, 800, 1045, 1298, 1669, 2088, 2628, 3258, 4087, 5000, 6219, 7602, 9331, 11368, 13877, 16754, 20368, 24536, 29580, 35468, 42624, 50845, 60827, 72357, 86078, 102100, 121101
Offset: 0

Views

Author

Gus Wiseman, Apr 15 2021

Keywords

Comments

First differs from A343345 at a(14) = 80, A343345(14) = 79.
Alternative name: Number of integer partitions of n with either no part dividing, or no part divisible by all the others.

Examples

			The a(0) = 1 through a(10) = 16 partitions (empty columns indicated by dots):
  ()  .  .  .  .  (32)  (321)  (43)    (53)     (54)      (64)
                               (52)    (332)    (72)      (73)
                               (322)   (431)    (432)     (433)
                               (3211)  (521)    (522)     (532)
                                       (3221)   (531)     (541)
                                       (32111)  (3222)    (721)
                                                (3321)    (3322)
                                                (4311)    (4321)
                                                (5211)    (5221)
                                                (32211)   (5311)
                                                (321111)  (32221)
                                                          (33211)
                                                          (43111)
                                                          (52111)
                                                          (322111)
                                                          (3211111)
		

Crossrefs

The complement is counted by A130714.
The first condition alone gives A338470.
The second condition alone gives A343341.
The "and" instead of "or" version is A343342.
The Heinz numbers of these partitions are A343343.
The strict case is A343382.
A000009 counts strict partitions.
A000041 counts partitions.
A000070 counts partitions with a selected part.
A006128 counts partitions with a selected position.
A015723 counts strict partitions with a selected part.

Programs

  • Mathematica
    Table[Length[Select[IntegerPartitions[n],#=={}||!And@@IntegerQ/@(#/Min@@#)||!And@@IntegerQ/@(Max@@#/#)&]],{n,0,30}]

A343347 Number of strict integer partitions of n with a part divisible by all the others.

Original entry on oeis.org

1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4, 6, 5, 4, 6, 6, 6, 8, 7, 7, 10, 9, 9, 12, 10, 8, 11, 11, 10, 14, 13, 11, 13, 12, 15, 20, 17, 15, 19, 19, 19, 22, 18, 17, 23, 22, 22, 28, 25, 24, 31, 28, 26, 32, 32, 30, 34, 32, 29, 37, 33, 27, 36, 33, 34, 44, 38, 36, 45, 45
Offset: 0

Views

Author

Gus Wiseman, Apr 16 2021

Keywords

Comments

Alternative name: Number of strict integer partitions of n that are empty or have greatest part divisible by all the others.

Examples

			The a(1) = 1 through a(15) = 6 partitions (A..F = 10..15):
  1  2  3   4   5   6   7    8   9    A    B    C     D    E    F
        21  31  41  42  61   62  63   82   A1   84    C1   C2   A5
                    51  421  71  81   91   632  93    841  D1   C3
                                 621  631  821  A2    931  842  E1
                                                B1    A21       C21
                                                6321            8421
		

Crossrefs

The dual version is A097986 (non-strict: A083710).
The non-strict version is A130689 (Heinz numbers: complement of A343337).
The strict complement is counted by A343377.
The case with smallest part divisible by all the others is A343378.
The case with smallest part not divisible by all the others is A343380.
A000005 counts divisors.
A000009 counts strict partitions.
A000070 counts partitions with a selected part.
A015723 counts strict partitions with a selected part.
A018818 counts partitions into divisors (strict: A033630).
A167865 counts strict chains of divisors > 1 summing to n.
A339564 counts factorizations with a selected factor.

Programs

  • Mathematica
    Table[Length[Select[IntegerPartitions[n],#=={}||UnsameQ@@#&&And@@IntegerQ/@(Max@@#/#)&]],{n,0,30}]
  • PARI
    seq(n)={Vec(1 + sum(m=1, n, my(u=divisors(m)); x^m*prod(i=1, #u-1, 1 + x^u[i] + O(x^(n-m+1)))))} \\ Andrew Howroyd, Apr 17 2021

Formula

G.f.: 1 + Sum_{k>0} (x^k/(1 + x^k))*Product_{d|k} (1 + x^d). - Andrew Howroyd, Apr 17 2021

A343338 Numbers with no prime index dividing or divisible by all the other prime indices.

Original entry on oeis.org

1, 15, 33, 35, 45, 51, 55, 69, 75, 77, 85, 91, 93, 95, 99, 105, 119, 123, 135, 141, 143, 145, 153, 155, 161, 165, 175, 177, 187, 201, 203, 205, 207, 209, 215, 217, 219, 221, 225, 231, 245, 247, 249, 253, 255, 265, 275, 279, 285, 287, 291, 295, 297, 299, 301
Offset: 1

Views

Author

Gus Wiseman, Apr 13 2021

Keywords

Comments

Alternative name: 1 and numbers whose smallest prime index does not divide all the other prime indices, nor whose greatest prime index is divisible by all the other prime indices.
First differs from A302697 in having 91.
First differs from A337987 in having 91.
A prime index of n is a number m such that prime(m) divides n. The multiset of prime indices of n is row n of A112798.
Also Heinz numbers of partitions with greatest part not divisible by all the others and smallest part not dividing all the others (counted by A343342). The Heinz number of a partition (y_1,...,y_k) is prime(y_1)*...*prime(y_k), giving a bijective correspondence between positive integers and integer partitions.

Examples

			The sequence of terms together with their prime indices begins:
      1: {}         105: {2,3,4}      203: {4,10}
     15: {2,3}      119: {4,7}        205: {3,13}
     33: {2,5}      123: {2,13}       207: {2,2,9}
     35: {3,4}      135: {2,2,2,3}    209: {5,8}
     45: {2,2,3}    141: {2,15}       215: {3,14}
     51: {2,7}      143: {5,6}        217: {4,11}
     55: {3,5}      145: {3,10}       219: {2,21}
     69: {2,9}      153: {2,2,7}      221: {6,7}
     75: {2,3,3}    155: {3,11}       225: {2,2,3,3}
     77: {4,5}      161: {4,9}        231: {2,4,5}
     85: {3,7}      165: {2,3,5}      245: {3,4,4}
     91: {4,6}      175: {3,3,4}      247: {6,8}
     93: {2,11}     177: {2,17}       249: {2,23}
     95: {3,8}      187: {5,7}        253: {5,9}
     99: {2,2,5}    201: {2,19}       255: {2,3,7}
For example, the prime indices of 975 are {2,3,3,6}, all of which divide 6, but not all of which are multiples of 2, so 975 is not in the sequence.
		

Crossrefs

The first condition alone gives A342193.
The second condition alone gives A343337.
The half-opposite versions are A343339 and A343340.
The partitions with these Heinz numbers are counted by A343342.
The opposite version is the complement of A343343.
A000005 counts divisors.
A000070 counts partitions with a selected part.
A001055 counts factorizations.
A056239 adds up prime indices, row sums of A112798.
A067824 counts strict chains of divisors starting with n.
A253249 counts strict chains of divisors.
A339564 counts factorizations with a selected factor.

Programs

  • Mathematica
    Select[Range[100],#==1||With[{p=PrimePi/@First/@FactorInteger[#]},!And@@IntegerQ/@(Max@@p/p)&&!And@@IntegerQ/@(p/Min@@p)]&]

Formula

Intersection of A342193 and A343337.

A343345 Number of integer partitions of n that are empty, or have smallest part dividing all the others, but do not have greatest part divisible by all the others.

Original entry on oeis.org

1, 0, 0, 0, 0, 0, 1, 1, 4, 6, 11, 16, 29, 36, 59, 79, 115, 149, 216, 270, 379, 473, 634, 793, 1063, 1292, 1689, 2079, 2667, 3241, 4142, 4982, 6291, 7582, 9434, 11321, 14049, 16709, 20545, 24490, 29860, 35380, 43004, 50741, 61282, 72284, 86680, 101906, 121990
Offset: 0

Views

Author

Gus Wiseman, Apr 15 2021

Keywords

Comments

First differs from A343346 at a(14) = 79, A343346(14) = 80.
Alternative name: Number of integer partitions of n with a part dividing all the others, but with no part divisible by all the others.

Examples

			The a(6) = 1 through a(11) = 16 partitions:
  (321)  (3211)  (431)    (531)     (541)      (641)
                 (521)    (3321)    (721)      (731)
                 (3221)   (4311)    (4321)     (4331)
                 (32111)  (5211)    (5221)     (5321)
                          (32211)   (5311)     (5411)
                          (321111)  (32221)    (7211)
                                    (33211)    (33221)
                                    (43111)    (43211)
                                    (52111)    (52211)
                                    (322111)   (53111)
                                    (3211111)  (322211)
                                               (332111)
                                               (431111)
                                               (521111)
                                               (3221111)
                                               (32111111)
		

Crossrefs

The first condition alone gives A083710.
The half-opposite versions are A130714 and A343342.
The Heinz numbers of these partitions are 1 and A343340.
The second condition alone gives A343341.
The opposite version is A343344.
The strict case is A343381.
A000009 counts strict partitions.
A000041 counts partitions.
A000070 counts partitions with a selected part.
A006128 counts partitions with a selected position.
A015723 counts strict partitions with a selected part.
A018818 counts partitions into divisors (strict: A033630).

Programs

  • Mathematica
    Table[Length[Select[IntegerPartitions[n],#=={}||And@@IntegerQ/@(#/Min@@#)&&!And@@IntegerQ/@(Max@@#/#)&]],{n,0,30}]

A343381 Number of strict integer partitions of n with a part dividing all the others but no part divisible by all the others.

Original entry on oeis.org

1, 0, 0, 0, 0, 0, 1, 0, 2, 1, 3, 3, 6, 4, 9, 9, 14, 14, 20, 20, 30, 30, 39, 44, 59, 59, 77, 85, 106, 114, 145, 150, 191, 205, 247, 267, 328, 345, 418, 455, 544, 582, 699, 745, 886, 962, 1117, 1209, 1430, 1523, 1778, 1932, 2225, 2406, 2792, 3001, 3456, 3750
Offset: 0

Views

Author

Gus Wiseman, Apr 16 2021

Keywords

Comments

Alternative name: Number of strict integer partitions of n that are empty or (1) have smallest part dividing all the others and (2) have greatest part not divisible by all the others.

Examples

			The a(6) = 1 through a(16) = 14 partitions (empty column indicated by dot, A..D = 10..13):
  321   .  431   531   541    641    642    751    761    861     862
           521         721    731    651    5431   851    951     871
                       4321   5321   741    6421   941    A41     961
                                     831    7321   A31    B31     A42
                                     921           B21    6531    B41
                                     5421          6431   7431    D21
                                                   6521   7521    6541
                                                   7421   9321    7531
                                                   8321   54321   7621
                                                                  8431
                                                                  8521
                                                                  9421
                                                                  A321
                                                                  64321
		

Crossrefs

The first condition alone gives A097986.
The non-strict version is A343345 (Heinz numbers: A343340).
The second condition alone gives A343377.
The half-opposite versions are A343378 and A343379.
The opposite (and dual) version is A343380.
A000005 counts divisors.
A000009 counts strict partitions.
A000070 counts partitions with a selected part.
A006128 counts partitions with a selected position.
A015723 counts strict partitions with a selected part.
A018818 counts partitions into divisors (strict: A033630).
A167865 counts strict chains of divisors > 1 summing to n.
A339564 counts factorizations with a selected factor.

Programs

  • Mathematica
    Table[Length[Select[IntegerPartitions[n],#=={}||UnsameQ@@#&&And@@IntegerQ/@(#/Min@@#)&&!And@@IntegerQ/@(Max@@#/#)&]],{n,0,30}]

A339619 Number of integer partitions of n with no 1's and a part divisible by all the other parts.

Original entry on oeis.org

1, 0, 1, 1, 2, 1, 4, 1, 5, 3, 7, 2, 13, 2, 13, 9, 17, 6, 27, 7, 33, 19, 35, 16, 58, 22, 58, 39, 75, 37, 108, 44, 117, 75, 132, 88, 190, 94, 199, 147, 250, 153, 322, 180, 363, 271, 405, 286, 544, 339, 601, 458, 699, 503, 868, 608, 990, 777, 1113, 865, 1422, 993
Offset: 0

Views

Author

Gus Wiseman, Apr 18 2021

Keywords

Comments

Alternative name: Number of integer partitions of n with no 1's that are empty or have greatest part divisible by all the other parts.

Examples

			The a(6) = 4 through a(16) = 17 partitions (A..G = 10..16):
  6    7  8     9    A      B    C       D     E        F      G
  33      44    63   55     632  66      6322  77       A5     88
  42      62    333  82          84            C2       C3     C4
  222     422        442         93            662      555    E2
          2222       622         A2            842      663    844
                     4222        444           A22      933    C22
                     22222       633           4442     6333   4444
                                 822           6332     33333  6622
                                 3333          8222     63222  8422
                                 4422          44222           A222
                                 6222          62222           44422
                                 42222         422222          63322
                                 222222        2222222         82222
                                                               442222
                                                               622222
                                                               4222222
                                                               22222222
		

Crossrefs

The dual version is A083711.
The version with 1's allowed is A130689.
The strict case is A339660.
The Heinz numbers of these partitions are the odd complement of A343337.
The strict case with 1's allowed is A343347.
A000009 counts strict partitions.
A000041 counts partitions.
A000070 counts partitions with a selected part.
A006128 counts partitions with a selected position.
A015723 counts strict partitions with a selected part.

Programs

  • Mathematica
    Table[If[n==0,1,Length[Select[IntegerPartitions[n],FreeQ[#,1]&&Or@@And@@IntegerQ/@(Max@@#/#)&]]],{n,0,30}]

A343343 Numbers with either no prime index dividing, or no prime index divisible by all the other prime indices.

Original entry on oeis.org

1, 15, 30, 33, 35, 45, 51, 55, 60, 66, 69, 70, 75, 77, 85, 90, 91, 93, 95, 99, 102, 105, 110, 119, 120, 123, 132, 135, 138, 140, 141, 143, 145, 150, 153, 154, 155, 161, 165, 170, 175, 177, 180, 182, 186, 187, 190, 195, 198, 201, 203, 204, 205, 207, 209, 210
Offset: 1

Views

Author

Gus Wiseman, Apr 15 2021

Keywords

Comments

After 1, first differs from A318992 in lacking 390, with prime indices {1,2,3,6}.
First differs from A343337 in having 195, with prime indices {2,3,6}.
Alternative name: 1 and numbers where either the smallest prime index is not a divisor of all the other prime indices, or the greatest prime index is not divisible by all the other prime indices.
A prime index of n is a number m such that prime(m) divides n. The multiset of prime indices of n is row n of A112798.
Also Heinz numbers of partitions that either empty, have smallest part not dividing all the others, or have greatest part not divisible by all the others (counted by A343346). The Heinz number of a partition (y_1,...,y_k) is prime(y_1)*...*prime(y_k), giving a bijective correspondence between positive integers and integer partitions.

Examples

			The sequence of terms together with their prime indices begins:
      1: {}            90: {1,2,2,3}      141: {2,15}
     15: {2,3}         91: {4,6}          143: {5,6}
     30: {1,2,3}       93: {2,11}         145: {3,10}
     33: {2,5}         95: {3,8}          150: {1,2,3,3}
     35: {3,4}         99: {2,2,5}        153: {2,2,7}
     45: {2,2,3}      102: {1,2,7}        154: {1,4,5}
     51: {2,7}        105: {2,3,4}        155: {3,11}
     55: {3,5}        110: {1,3,5}        161: {4,9}
     60: {1,1,2,3}    119: {4,7}          165: {2,3,5}
     66: {1,2,5}      120: {1,1,1,2,3}    170: {1,3,7}
     69: {2,9}        123: {2,13}         175: {3,3,4}
     70: {1,3,4}      132: {1,1,2,5}      177: {2,17}
     75: {2,3,3}      135: {2,2,2,3}      180: {1,1,2,2,3}
     77: {4,5}        138: {1,2,9}        182: {1,4,6}
     85: {3,7}        140: {1,1,3,4}      186: {1,2,11}
For example, the prime indices of 90 are {1,2,2,3}, and, because 1 divides all the other parts, 90 is in the sequence, even though 3 is not divisible by all the other parts.
		

Crossrefs

The partitions without these Heinz numbers are counted by A130714.
The first condition alone gives A342193.
The second condition alone gives A343337.
The "and" instead of "or" version is A343338.
The partitions with these Heinz numbers are counted by A343346.
A000005 counts divisors.
A000070 counts partitions with a selected part.
A006128 counts partitions with a selected position.
A015723 counts strict partitions with a selected part.
A018818 counts partitions into divisors (strict: A033630).
A056239 adds up prime indices, row sums of A112798.
A067824 counts strict chains of divisors starting with n.
A253249 counts strict chains of divisors.
A339564 counts factorizations with a selected factor.

Programs

  • Mathematica
    Select[Range[100],#==1||With[{p=PrimePi/@First/@FactorInteger[#]},!And@@IntegerQ/@(Max@@p/p)||!And@@IntegerQ/@(p/Min@@p)]&]

Formula

Equals the union of A342193 and A343337.

A343340 Numbers with a prime index dividing all the other prime indices, but with no prime index divisible by all the other prime indices.

Original entry on oeis.org

30, 60, 66, 70, 90, 102, 110, 120, 132, 138, 140, 150, 154, 170, 180, 182, 186, 190, 198, 204, 210, 220, 238, 240, 246, 264, 270, 273, 276, 280, 282, 286, 290, 300, 306, 308, 310, 322, 330, 340, 350, 354, 360, 364, 372, 374, 380, 396, 402, 406, 408, 410, 414
Offset: 1

Views

Author

Gus Wiseman, Apr 15 2021

Keywords

Comments

Alternative name: Numbers > 1 whose smallest prime index divides all the other prime indices, but whose greatest prime index is not divisible by all the other prime indices.
A prime index of n is a number m such that prime(m) divides n. The multiset of prime indices of n is row n of A112798.
Also Heinz numbers of partitions with greatest part not divisible by all the others, but smallest part dividing all the others (counted by A343345). The Heinz number of a partition (y_1,...,y_k) is prime(y_1)*...*prime(y_k), giving a bijective correspondence between positive integers and integer partitions.

Examples

			The sequence of terms together with their prime indices begins:
     30: {1,2,3}        182: {1,4,6}          282: {1,2,15}
     60: {1,1,2,3}      186: {1,2,11}         286: {1,5,6}
     66: {1,2,5}        190: {1,3,8}          290: {1,3,10}
     70: {1,3,4}        198: {1,2,2,5}        300: {1,1,2,3,3}
     90: {1,2,2,3}      204: {1,1,2,7}        306: {1,2,2,7}
    102: {1,2,7}        210: {1,2,3,4}        308: {1,1,4,5}
    110: {1,3,5}        220: {1,1,3,5}        310: {1,3,11}
    120: {1,1,1,2,3}    238: {1,4,7}          322: {1,4,9}
    132: {1,1,2,5}      240: {1,1,1,1,2,3}    330: {1,2,3,5}
    138: {1,2,9}        246: {1,2,13}         340: {1,1,3,7}
    140: {1,1,3,4}      264: {1,1,1,2,5}      350: {1,3,3,4}
    150: {1,2,3,3}      270: {1,2,2,2,3}      354: {1,2,17}
    154: {1,4,5}        273: {2,4,6}          360: {1,1,1,2,2,3}
    170: {1,3,7}        276: {1,1,2,9}        364: {1,1,4,6}
    180: {1,1,2,2,3}    280: {1,1,1,3,4}      372: {1,1,2,11}
		

Crossrefs

The first condition alone gives the complement of A342193.
The second condition alone gives A343337.
The partitions with these Heinz numbers are counted by A343345.
A000005 counts divisors.
A000070 counts partitions with a selected part.
A001055 counts factorizations.
A056239 adds up prime indices, row sums of A112798.
A067824 counts strict chains of divisors starting with n.
A253249 counts strict chains of divisors.

Programs

  • Mathematica
    Select[Range[2,100],With[{p=PrimePi/@First/@FactorInteger[#]},!And@@IntegerQ/@(Max@@p/p)&&And@@IntegerQ/@(p/Min@@p)]&]

Formula

Complement of A342193 in A343337.

A339660 Number of strict integer partitions of n with no 1's and a part divisible by all the other parts.

Original entry on oeis.org

1, 0, 1, 1, 1, 1, 2, 1, 2, 2, 2, 2, 4, 1, 3, 3, 3, 3, 5, 2, 5, 5, 4, 5, 7, 3, 5, 6, 5, 5, 9, 4, 7, 6, 6, 9, 11, 6, 9, 10, 9, 10, 12, 6, 11, 12, 10, 12, 16, 9, 15, 16, 12, 14, 18, 14, 16, 18, 14, 15, 22, 11, 16, 20, 13, 21, 23, 15, 21, 24, 21, 21, 31, 14, 24
Offset: 0

Views

Author

Gus Wiseman, Apr 19 2021

Keywords

Comments

Alternative name: Number of strict integer partitions of n with no 1's that are empty or have greatest part divisible by all the other parts.

Examples

			The a(n) partitions for n = 14, 12, 18, 24, 30, 39, 36:
  (14)     (12)    (18)      (24)        (30)        (39)          (36)
  (12,2)   (8,4)   (12,6)    (16,8)      (24,6)      (36,3)        (27,9)
  (8,4,2)  (9,3)   (15,3)    (18,6)      (25,5)      (26,13)       (30,6)
           (10,2)  (16,2)    (20,4)      (27,3)      (27,9,3)      (32,4)
                   (12,4,2)  (21,3)      (28,2)      (28,7,4)      (33,3)
                             (22,2)      (20,10)     (30,6,3)      (34,2)
                             (12,6,4,2)  (18,9,3)    (24,12,3)     (24,12)
                                         (24,4,2)    (24,8,4,3)    (24,8,4)
                                         (16,8,4,2)  (20,10,5,4)   (18,9,6,3)
                                                     (24,6,4,3,2)  (24,6,4,2)
                                                                   (20,10,4,2)
		

Crossrefs

The dual version is A098965 (non-strict: A083711).
The non-strict version is A339619 (Heinz numbers: complement of A343337).
The version with 1's allowed is A343347 (non-strict: A130689).
The case without a part dividing all the other parts is A343380.
A000009 counts strict partitions.
A000070 counts partitions with a selected part.
A015723 counts strict partitions with a selected part.
A018818 counts partitions into divisors (strict: A033630).
A167865 counts strict chains of divisors > 1 summing to n.

Programs

  • Mathematica
    Table[If[n==0,1,Length[Select[IntegerPartitions[n],FreeQ[#,1]&&UnsameQ@@#&&And@@IntegerQ/@(Max@@#/#)&]]],{n,0,30}]
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