A320322
Number of integer partitions of n whose product is a perfect power.
Original entry on oeis.org
1, 0, 0, 0, 2, 2, 5, 5, 9, 11, 18, 19, 28, 30, 42, 50, 68, 76, 102, 113, 146, 170, 212, 241, 312, 356, 441, 514, 628, 720, 887, 1008, 1215, 1403, 1660, 1903, 2291, 2609, 3107, 3594, 4254, 4864, 5739, 6546, 7672, 8811, 10237, 11651, 13583, 15420, 17867, 20382
Offset: 0
The a(4) = 2 through a(11) = 19 integer partitions:
4 41 33 331 8 9 55 551
22 221 42 421 44 81 82 632
222 2221 422 333 91 821
411 4111 2222 441 433 911
2211 22111 3311 4221 442 4331
4211 22221 811 4421
22211 33111 3322 8111
41111 42111 3331 33221
221111 222111 4222 33311
411111 4411 42221
2211111 22222 44111
42211 222221
222211 422111
331111 2222111
421111 3311111
2221111 4211111
4111111 22211111
22111111 41111111
221111111
-
Table[Length[Select[IntegerPartitions[n],GCD@@FactorInteger[Times@@#][[All,2]]>1&]],{n,30}]
A320324
Numbers of which each prime index has the same number of prime factors, counted with multiplicity.
Original entry on oeis.org
1, 2, 3, 4, 5, 7, 8, 9, 11, 13, 15, 16, 17, 19, 23, 25, 27, 29, 31, 32, 33, 37, 41, 43, 45, 47, 49, 51, 53, 55, 59, 61, 64, 67, 71, 73, 75, 79, 81, 83, 85, 89, 91, 93, 97, 99, 101, 103, 107, 109, 113, 121, 123, 125, 127, 128, 131, 135, 137, 139, 149, 151, 153
Offset: 1
The terms together with their corresponding multiset multisystems (A302242):
1: {}
2: {{}}
3: {{1}}
4: {{},{}}
5: {{2}}
7: {{1,1}}
8: {{},{},{}}
9: {{1},{1}}
11: {{3}}
13: {{1,2}}
15: {{1},{2}}
16: {{},{},{},{}}
17: {{4}}
19: {{1,1,1}}
23: {{2,2}}
25: {{2},{2}}
27: {{1},{1},{1}}
29: {{1,3}}
31: {{5}}
32: {{},{},{},{},{}}
33: {{1},{3}}
37: {{1,1,2}}
41: {{6}}
43: {{1,4}}
45: {{1},{1},{2}}
47: {{2,3}}
49: {{1,1},{1,1}}
Cf.
A001222,
A038041,
A112798,
A302242,
A306017,
A317583,
A319066,
A319169,
A320325,
A322794,
A326533,
A326534,
A326535,
A326536,
A326537.
-
Select[Range[100],SameQ@@PrimeOmega/@PrimePi/@First/@FactorInteger[#]&]
-
is(n) = #Set(apply(p -> bigomega(primepi(p)), factor(n)[,1]~))<=1 \\ Rémy Sigrist, Oct 11 2018
A358836
Number of multiset partitions of integer partitions of n with all distinct block sizes.
Original entry on oeis.org
1, 1, 2, 4, 8, 15, 28, 51, 92, 164, 289, 504, 871, 1493, 2539, 4290, 7201, 12017, 19939, 32911, 54044, 88330, 143709, 232817, 375640, 603755, 966816, 1542776, 2453536, 3889338, 6146126, 9683279, 15211881, 23830271, 37230720, 58015116, 90174847, 139820368, 216286593
Offset: 0
The a(1) = 1 through a(5) = 15 multiset partitions:
{1} {2} {3} {4} {5}
{1,1} {1,2} {1,3} {1,4}
{1,1,1} {2,2} {2,3}
{1},{1,1} {1,1,2} {1,1,3}
{1,1,1,1} {1,2,2}
{1},{1,2} {1,1,1,2}
{2},{1,1} {1},{1,3}
{1},{1,1,1} {1},{2,2}
{2},{1,2}
{3},{1,1}
{1,1,1,1,1}
{1},{1,1,2}
{2},{1,1,1}
{1},{1,1,1,1}
{1,1},{1,1,1}
From _Gus Wiseman_, Aug 21 2024: (Start)
The a(0) = 1 through a(5) = 15 compositions whose leaders of maximal weakly decreasing runs are strictly increasing:
() (1) (2) (3) (4) (5)
(11) (12) (13) (14)
(21) (22) (23)
(111) (31) (32)
(112) (41)
(121) (113)
(211) (122)
(1111) (131)
(221)
(311)
(1112)
(1121)
(1211)
(2111)
(11111)
(End)
The version for set partitions is
A007837.
For sums instead of sizes we have
A271619.
For constant instead of distinct sizes we have
A319066.
These multiset partitions are ranked by
A326533.
For odd instead of distinct sizes we have
A356932.
The version for twice-partitions is
A358830.
The case of distinct sums also is
A358832.
Ranked by positions of strictly increasing rows in
A374740, opposite
A374629.
A001970 counts multiset partitions of integer partitions.
A335456 counts patterns matched by compositions.
-
sps[{}]:={{}};sps[set:{i_,_}]:=Join@@Function[s,Prepend[#,s]&/@sps[Complement[set,s]]]/@Cases[Subsets[set],{i,_}];
mps[set_]:=Union[Sort[Sort/@(#/.x_Integer:>set[[x]])]&/@sps[Range[Length[set]]]];
Table[Length[Select[Join@@mps/@IntegerPartitions[n],UnsameQ@@Length/@#&]],{n,0,10}]
(* second program *)
Table[Length[Select[Join@@Permutations/@IntegerPartitions[n], Less@@First/@Split[#,GreaterEqual]&]],{n,0,15}] (* Gus Wiseman, Aug 21 2024 *)
-
P(n,y) = {1/prod(k=1, n, 1 - y*x^k + O(x*x^n))}
seq(n) = {my(g=P(n,y)); Vec(prod(k=1, n, 1 + polcoef(g, k, y) + O(x*x^n)))} \\ Andrew Howroyd, Dec 31 2022
A320325
Numbers whose product of prime indices is a perfect power.
Original entry on oeis.org
7, 9, 14, 18, 19, 21, 23, 25, 27, 28, 36, 38, 42, 46, 49, 50, 53, 54, 56, 57, 63, 72, 76, 81, 84, 92, 97, 98, 100, 103, 106, 108, 112, 114, 115, 121, 125, 126, 131, 133, 144, 147, 151, 152, 159, 161, 162, 168, 169, 171, 175, 183, 184, 185, 189, 194, 195, 196
Offset: 1
The terms together with their corresponding multiset multisystems (A302242):
7: {{1,1}}
9: {{1},{1}}
14: {{},{1,1}}
18: {{},{1},{1}}
19: {{1,1,1}}
21: {{1},{1,1}}
23: {{2,2}}
25: {{2},{2}}
27: {{1},{1},{1}}
28: {{},{},{1,1}}
36: {{},{},{1},{1}}
38: {{},{1,1,1}}
42: {{},{1},{1,1}}
46: {{},{2,2}}
49: {{1,1},{1,1}}
50: {{},{2},{2}}
53: {{1,1,1,1}}
54: {{},{1},{1},{1}}
56: {{},{},{},{1,1}}
57: {{1},{1,1,1}}
63: {{1},{1},{1,1}}
72: {{},{},{},{1},{1}}
76: {{},{},{1,1,1}}
81: {{1},{1},{1},{1}}
Cf.
A000720,
A001222,
A001597,
A003963,
A056239,
A064573,
A112798,
A302242,
A305551,
A306017,
A319056,
A319066,
A320322,
A320323,
A320324.
-
Select[Range[100],GCD@@FactorInteger[Times@@Cases[FactorInteger[#],{p_,k_}:>PrimePi[p]^k]][[All,2]]>1&]
A101509
Binomial transform of tau(n) (see A000005).
Original entry on oeis.org
1, 3, 7, 16, 35, 75, 159, 334, 696, 1442, 2976, 6123, 12562, 25706, 52492, 107014, 217877, 443061, 899957, 1826078, 3701783, 7498261, 15178255, 30706320, 62085915, 125465715, 253415981, 511608490, 1032427637, 2082680887, 4199956101, 8467124805, 17064784905, 34382825363, 69256687719, 139465867773
Offset: 0
From _Gus Wiseman_, Jan 16 2019: (Start)
The a(3) = 16 ways to arrange the parts of an integer partition of 4 into a matrix:
[4] [1 3] [3 1] [2 2] [1 1 2] [1 2 1] [2 1 1] [1 1 1 1]
.
[1] [3] [2] [1 1]
[3] [1] [2] [1 1]
.
[1] [1] [2]
[1] [2] [1]
[2] [1] [1]
.
[1]
[1]
[1]
[1]
(End)
-
bintr:= proc(p) proc(n) add(p(k) *binomial(n, k), k=0..n) end end:
a:= bintr(n-> numtheory[tau](n+1)):
seq(a(n), n=0..40); # Alois P. Heinz, Jan 30 2011
-
a[n_] := Sum[DivisorSigma[0, k+1]*Binomial[n, k], {k, 0, n}]; Table[a[n], {n, 0, 40}] (* Jean-François Alcover, Feb 18 2017 *)
-
A101509(n) = sum( k=0,n, numdiv(k+1)*binomial(n,k)) \\ M. F. Hasler, Jan 14 2009
A319169
Number of integer partitions of n whose parts all have the same number of prime factors, counted with multiplicity.
Original entry on oeis.org
1, 1, 2, 2, 3, 3, 4, 4, 6, 6, 8, 7, 11, 11, 14, 15, 20, 19, 26, 27, 34, 35, 43, 45, 59, 60, 72, 77, 94, 98, 118, 125, 148, 158, 184, 198, 233, 245, 282, 308, 353, 374, 428, 464, 525, 566, 635, 686, 779, 832, 930, 1005, 1123, 1208, 1345, 1451, 1609, 1732, 1912
Offset: 0
The a(1) = 1 through a(9) = 6 integer partitions:
1 2 3 4 5 6 7 8 9
11 111 22 32 33 52 44 72
1111 11111 222 322 53 333
111111 1111111 332 522
2222 3222
11111111 111111111
Cf.
A000607,
A001222,
A003963,
A064573,
A279787,
A305551,
A319056,
A319066,
A319071,
A320322,
A320324.
-
b:= proc(n, i, f) option remember; `if`(n=0, 1, `if`(i<1, 0,
b(n, i-1, f)+(o-> `if`(f in {0, o}, b(n-i, min(i, n-i),
`if`(f=0, o, f)), 0))(numtheory[bigomega](i))))
end:
a:= n-> b(n$2, 0):
seq(a(n), n=0..75); # Alois P. Heinz, Dec 15 2018
-
Table[Length[Select[IntegerPartitions[n],SameQ@@PrimeOmega/@#&]],{n,30}]
(* Second program: *)
b[n_, i_, f_] := b[n, i, f] = If[n == 0, 1, If[i < 1, 0,
b[n, i-1, f] + Function[o, If[f == 0 || f == o, b[n-i, Min[i, n-i],
If[f == 0, o, f]], 0]][PrimeOmega[i]]]];
a[n_] := b[n, n, 0];
a /@ Range[0, 75] (* Jean-François Alcover, May 10 2021, after Alois P. Heinz *)
A323433
Number of ways to split an integer partition of n into consecutive subsequences of equal length.
Original entry on oeis.org
1, 1, 3, 5, 10, 14, 25, 34, 54, 74, 109, 146, 211, 276, 381, 501, 675, 871, 1156, 1477, 1926, 2447, 3142, 3957, 5038, 6291, 7918, 9839, 12277, 15148, 18773, 23027, 28333, 34587, 42284, 51357, 62466, 75503, 91344, 109971, 132421, 158755, 190365, 227354, 271511
Offset: 0
The a(5) = 14 split partitions:
[5] [4 1] [3 2] [3 1 1] [2 2 1] [2 1 1 1] [1 1 1 1 1]
.
[4] [3] [2 1]
[1] [2] [1 1]
.
[3] [2]
[1] [2]
[1] [1]
.
[2]
[1]
[1]
[1]
.
[1]
[1]
[1]
[1]
[1]
Cf.
A000005,
A000219,
A008284,
A101509,
A316245,
A319066,
A323295,
A323300,
A323307,
A323429,
A323434.
-
b:= proc(n, i, t) option remember; `if`(n=0 or i=1, numtheory
[tau](t+n), b(n, i-1, t)+b(n-i, min(n-i, i), t+1))
end:
a:= n-> `if`(n=0, 1, b(n$2, 0)):
seq(a(n), n=0..50); # Alois P. Heinz, Jan 15 2019
-
Table[Sum[Length[Divisors[Length[ptn]]],{ptn,IntegerPartitions[n]}],{n,30}]
(* Second program: *)
b[n_, i_, t_] := b[n, i, t] = If[n == 0 || i == 1,
DivisorSigma[0, t+n], b[n, i-1, t] + b[n-i, Min[n-i, i], t+1]];
a[n_] := If[n == 0, 1, b[n, n, 0]];
a /@ Range[0, 50] (* Jean-François Alcover, May 10 2021, after Alois P. Heinz *)
-
my(N=66, x='x+O('x^N)); Vec(1+sum(k=1, N, numdiv(k)*x^k/prod(j=1, k, 1-x^j))) \\ Seiichi Manyama, Jan 21 2022
-
my(N=66, x='x+O('x^N)); Vec(1+sum(i=1, N, sum(j=1, N\i, x^(i*j)/prod(k=1, i*j, 1-x^k)))) \\ Seiichi Manyama, Jan 21 2022
A323429
Number of rectangular plane partitions of n.
Original entry on oeis.org
1, 1, 3, 5, 10, 14, 26, 35, 58, 81, 124, 169, 257, 345, 501, 684, 968, 1304, 1830, 2452, 3387, 4541, 6188, 8257, 11193, 14865, 19968, 26481, 35341, 46674, 62007, 81611, 107860, 141602, 186292, 243800, 319610, 416984, 544601, 708690, 922472, 1197018, 1553442
Offset: 0
The a(5) = 14 matrices:
[5] [4 1] [3 2] [3 1 1] [2 2 1] [2 1 1 1] [1 1 1 1 1]
.
[4] [3] [2 1]
[1] [2] [1 1]
.
[3] [2]
[1] [2]
[1] [1]
.
[2]
[1]
[1]
[1]
.
[1]
[1]
[1]
[1]
[1]
-
Table[Sum[Length[Select[Union[Sort/@Tuples[IntegerPartitions[#,{k}]&/@ptn]],And@@OrderedQ/@Transpose[#]&]],{ptn,IntegerPartitions[n]},{k,Min[ptn]}],{n,30}]
A007713
Number of 4-level rooted trees with n leaves.
Original entry on oeis.org
1, 1, 4, 10, 30, 75, 206, 518, 1344, 3357, 8429, 20759, 51044, 123973, 299848, 719197, 1716563, 4070800, 9607797, 22555988, 52718749, 122655485, 284207304, 655894527, 1508046031, 3454808143, 7887768997, 17949709753, 40719611684, 92096461012, 207697731344
Offset: 0
From _Gus Wiseman_, Oct 11 2018: (Start)
Also the number of multiset partitions of multiset partitions of integer partitions of n. For example, the a(1) = 1 through a(4) = 30 multiset partitions are:
((1)) ((2)) ((3)) ((4))
((11)) ((12)) ((13))
((1)(1)) ((111)) ((22))
((1))((1)) ((1)(2)) ((112))
((1)(11)) ((1111))
((1))((2)) ((1)(3))
((1))((11)) ((2)(2))
((1)(1)(1)) ((1)(12))
((1))((1)(1)) ((2)(11))
((1))((1))((1)) ((1)(111))
((11)(11))
((1))((3))
((2))((2))
((1))((12))
((1)(1)(2))
((2))((11))
((1))((111))
((1)(1)(11))
((11))((11))
((1))((1)(2))
((2))((1)(1))
((1))((1)(11))
((1)(1)(1)(1))
((11))((1)(1))
((1))((1))((2))
((1))((1))((11))
((1))((1)(1)(1))
((1)(1))((1)(1))
((1))((1))((1)(1))
((1))((1))((1))((1))
(End)
- Alois P. Heinz, Table of n, a(n) for n = 0..1000
- P. J. Cameron, Sequences realized by oligomorphic permutation groups, J. Integ. Seqs. Vol. 3 (2000), #00.1.5.
- B. A. Huberman and T. Hogg, Complexity and adaptation, Evolution, games and learning (Los Alamos, N.M., 1985). Phys. D 22 (1986), no. 1-3, 376-384.
- N. J. A. Sloane, Transforms
- Index entries for sequences related to rooted trees
Cf.
A001970,
A047968,
A050342,
A089259,
A141268,
A258466,
A261049,
A319066,
A320328,
A320330,
A320331.
-
with(numtheory): etr:= proc(p) local b; b:=proc(n) option remember; local d,j; if n=0 then 1 else add(add(d*p(d), d=divisors(j)) *b(n-j), j=1..n)/n fi end end: b0:= etr(1): b1:= etr(b0): a:= etr(b1): seq(a(n), n=0..30); # Alois P. Heinz, Sep 08 2008
-
i[ n_, m_ ] := 1 /; m==1 || n==0; i[ n_, m_ ] := (i[ n, m ]=1/n Sum[ i[ k, m ] Plus @@ ((# i[ #, m-1 ])& /@ Divisors[ n-k ]), {k, 0, n-1} ]) /; n>0 && m>1
etr[p_] := Module[{b}, b[n_] := b[n] = If[n == 0, 1, Sum[Sum[d*p[d], {d, Divisors[ j]}]*b[n-j], {j, 1, n}]/n]; b]; b0 = etr[Function[1]]; b1 = etr[b0]; a = etr[b1]; Table[a[n], {n, 1, 30}] (* Jean-François Alcover, Mar 05 2015, after Alois P. Heinz *)
A089299
Number of square plane partitions of n.
Original entry on oeis.org
1, 1, 1, 1, 2, 2, 4, 5, 8, 11, 16, 21, 31, 41, 57, 78, 108, 146, 202, 274, 375, 509, 690, 929, 1255, 1679, 2246, 2991, 3979, 5266, 6971, 9187, 12104, 15898, 20870, 27322, 35762, 46690, 60927, 79348, 103270, 134138, 174108, 225576, 291990, 377320, 487083
Offset: 0
a(7) = 5:
7 41 32 31 22
. 11 11 21 21
a(10) = 16 from {{10}}, {{3, 2}, {3, 2}}, {{3, 3}, {2, 2}}, {{3, 3}, {3, 1}}, {{4, 1}, {4, 1}}, {{4, 2}, {2, 2}}, {{4, 2}, {3, 1}}, {{4, 3}, {2, 1}}, {{4, 4}, {1, 1}}, {{5, 1}, {3, 1}}, {{5, 2}, {2, 1}}, {{5, 3}, {1, 1}}, {{6, 1}, {2, 1}}, {{6, 2}, {1, 1}}, {{7, 1}, {1, 1}}, {{2, 1, 1}, {1, 1, 1}, {1, 1, 1}}
From _Gus Wiseman_, Jan 16 2019: (Start)
The a(10) = 16 square plane partitions:
[ten]
.
[32] [33] [33] [41] [42] [42] [43] [44] [51] [52] [53] [61] [62] [71]
[32] [22] [31] [41] [22] [31] [21] [11] [31] [21] [11] [21] [11] [11]
.
[211]
[111]
[111]
(End)
-
Table[Sum[Length[Select[Union[Sort/@Tuples[IntegerPartitions[#,{Length[ptn]}]&/@ptn]],And@@OrderedQ/@Transpose[#]&]],{ptn,IntegerPartitions[n]}],{n,30}] (* Gus Wiseman, Jan 16 2019 *)
Showing 1-10 of 37 results.
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