A316413
Heinz numbers of integer partitions whose length divides their sum.
Original entry on oeis.org
2, 3, 4, 5, 7, 8, 9, 10, 11, 13, 16, 17, 19, 21, 22, 23, 25, 27, 28, 29, 30, 31, 32, 34, 37, 39, 41, 43, 46, 47, 49, 53, 55, 57, 59, 61, 62, 64, 67, 68, 71, 73, 78, 79, 81, 82, 83, 84, 85, 87, 88, 89, 90, 91, 94, 97, 98, 99, 100, 101, 103, 105, 107, 109, 110
Offset: 1
Sequence of partitions whose length divides their sum begins (1), (2), (11), (3), (4), (111), (22), (31), (5), (6), (1111), (7), (8), (42), (51), (9), (33), (222), (411).
Cf.
A056239,
A067538,
A074761,
A143773,
A237984,
A289508,
A289509,
A290103,
A296150,
A298423,
A316428,
A316431.
-
isA326413 := proc(n)
psigsu := A056239(n) ;
psigle := numtheory[bigomega](n) ;
if modp(psigsu,psigle) = 0 then
true;
else
false;
end if;
end proc:
n := 1:
for i from 2 to 3000 do
if isA326413(i) then
printf("%d %d\n",n,i);
n := n+1 ;
end if;
end do: # R. J. Mathar, Aug 09 2019
# second Maple program:
q:= n-> (l-> nops(l)>0 and irem(add(i, i=l), nops(l))=0)(map
(i-> numtheory[pi](i[1])$i[2], ifactors(n)[2])):
select(q, [$1..110])[]; # Alois P. Heinz, Nov 19 2021
-
Select[Range[2,100],Divisible[Total[Cases[FactorInteger[#],{p_,k_}:>k*PrimePi[p]]],PrimeOmega[#]]&]
A025065
Number of palindromic partitions of n.
Original entry on oeis.org
1, 1, 2, 2, 4, 4, 7, 7, 12, 12, 19, 19, 30, 30, 45, 45, 67, 67, 97, 97, 139, 139, 195, 195, 272, 272, 373, 373, 508, 508, 684, 684, 915, 915, 1212, 1212, 1597, 1597, 2087, 2087, 2714, 2714, 3506, 3506, 4508, 4508, 5763, 5763, 7338, 7338, 9296, 9296, 11732, 11732, 14742, 14742, 18460, 18460, 23025, 23025, 28629, 28629
Offset: 0
The partitions for the first few values of n are as follows:
n: partitions .......................... number
1: 1 ................................... 1
2: 2 11 ................................ 2
3: 3 111 ............................... 2
4: 4 22 121 1111 ....................... 4
5: 5 131 212 11111 ..................... 4
6: 6 141 33 222 1221 11211 111111 ...... 7
7: 7 151 313 11311 232 21112 1111111 ... 7
From _Reinhard Zumkeller_, Jan 23 2010: (Start)
Partitions into 1,2,4,6,... for the first values of n:
1: 1 ....................................... 1
2: 2 11 .................................... 2
3: 21 111 .................................. 2
4: 4 22 211 1111 ........................... 4
5: 41 221 2111 11111 ....................... 4
6: 6 42 4211 222 2211 21111 111111.......... 7
7: 61 421 42111 2221 22111 211111 1111111 .. 7. (End)
The ordered version (palindromic compositions) is
A016116.
The case of palindromic prime signature is
A242414.
Palindromic partitions are ranked by
A265640, with complement
A229153.
The case of palindromic plane trees is
A319436.
The multiplicative version (palindromic factorizations) is
A344417.
A000569 counts graphical partitions.
Cf.
A000041,
A067538,
A143773,
A209816,
A338914,
A338915,
A340387,
A344296,
A344414,
A344415,
A344416.
-
a025065 = p (1:[2,4..]) where
p [] _ = 0
p _ 0 = 1
p ks'@(k:ks) m | m < k = 0
| otherwise = p ks' (m - k) + p ks m
-- Reinhard Zumkeller, Aug 12 2011
-
import Data.List (group)
a025065 = length . filter (<= 1) .
map (sum . map ((`mod` 2) . length) . group) . ps 1
where ps x 0 = [[]]
ps x y = [t:ts | t <- [x..y], ts <- ps t (y - t)]
-- Reinhard Zumkeller, Dec 18 2013
-
Map[Length[Select[IntegerPartitions[#], Count[OddQ[Transpose[Tally[#]][[2]]], True] <= 1 &]] &, Range[40]] (* Peter J. C. Moses, Jan 20 2014 *)
n = 8; Select[IntegerPartitions[n], Count[OddQ[Transpose[Tally[#]][[2]]], True] <= 1 &] (* Peter J. C. Moses, Jan 20 2014 *)
CoefficientList[Series[1/((1 - x) Product[1 - x^(2 n), {n, 1, 50}]), {x, 0, 60}], x] (* Clark Kimberling, Mar 14 2014 *)
-
N=66; q='q+O('q^N); Vec( 1/((1-q)*eta(q^2)) ) \\ Joerg Arndt, Mar 11 2014
Prepended a(0)=1, added more terms,
Joerg Arndt, Mar 11 2014
A359893
Triangle read by rows where T(n,k) is the number of integer partitions of n with median k, where k ranges from 1 to n in steps of 1/2.
Original entry on oeis.org
1, 1, 0, 1, 1, 1, 0, 0, 1, 2, 0, 2, 0, 0, 0, 1, 3, 0, 1, 2, 0, 0, 0, 0, 1, 4, 1, 2, 0, 3, 0, 0, 0, 0, 0, 1, 6, 1, 3, 0, 1, 3, 0, 0, 0, 0, 0, 0, 1, 8, 1, 6, 0, 2, 0, 4, 0, 0, 0, 0, 0, 0, 0, 1, 11, 2, 7, 1, 3, 0, 1, 4, 0, 0, 0, 0, 0, 0, 0, 0, 1
Offset: 1
Triangle begins:
1
1 0 1
1 1 0 0 1
2 0 2 0 0 0 1
3 0 1 2 0 0 0 0 1
4 1 2 0 3 0 0 0 0 0 1
6 1 3 0 1 3 0 0 0 0 0 0 1
8 1 6 0 2 0 4 0 0 0 0 0 0 0 1
11 2 7 1 3 0 1 4 0 0 0 0 0 0 0 0 1
15 2 10 3 4 0 2 0 5 0 0 0 0 0 0 0 0 0 1
20 3 13 3 7 0 3 0 1 5 0 0 0 0 0 0 0 0 0 0 1
26 4 19 3 11 1 4 0 2 0 6 0 0 0 0 0 0 0 0 0 0 0 1
For example, row n = 8 counts the following partitions:
611 4211 422 . 332 . 44 . . . . . . . 8
5111 521 431 53
32111 2222 62
41111 3221 71
221111 3311
311111 22211
2111111
11111111
Row lengths are 2n-1 =
A005408(n-1).
The median statistic is ranked by
A360005(n)/2.
A240219 counts partitions w/ the same mean as median, complement
A359894.
-
Table[Length[Select[IntegerPartitions[n], Median[#]==k&]],{n,1,10},{k,1,n,1/2}]
A359901
Triangle read by rows where T(n,k) is the number of integer partitions of n with median k = 1..n.
Original entry on oeis.org
1, 1, 1, 1, 0, 1, 2, 2, 0, 1, 3, 1, 0, 0, 1, 4, 2, 3, 0, 0, 1, 6, 3, 1, 0, 0, 0, 1, 8, 6, 2, 4, 0, 0, 0, 1, 11, 7, 3, 1, 0, 0, 0, 0, 1, 15, 10, 4, 2, 5, 0, 0, 0, 0, 1, 20, 13, 7, 3, 1, 0, 0, 0, 0, 0, 1, 26, 19, 11, 4, 2, 6, 0, 0, 0, 0, 0, 1
Offset: 1
Triangle begins:
1
1 1
1 0 1
2 2 0 1
3 1 0 0 1
4 2 3 0 0 1
6 3 1 0 0 0 1
8 6 2 4 0 0 0 1
11 7 3 1 0 0 0 0 1
15 10 4 2 5 0 0 0 0 1
20 13 7 3 1 0 0 0 0 0 1
26 19 11 4 2 6 0 0 0 0 0 1
35 24 14 5 3 1 0 0 0 0 0 0 1
45 34 17 8 4 2 7 0 0 0 0 0 0 1
58 42 23 12 5 3 1 0 0 0 0 0 0 0 1
For example, row n = 9 counts the following partitions:
(7,1,1) (5,2,2) (3,3,3) (4,4,1) . . . . (9)
(6,1,1,1) (6,2,1) (4,3,2)
(3,3,1,1,1) (3,2,2,2) (5,3,1)
(4,2,1,1,1) (4,2,2,1)
(5,1,1,1,1) (4,3,1,1)
(3,2,1,1,1,1) (2,2,2,2,1)
(4,1,1,1,1,1) (3,2,2,1,1)
(2,2,1,1,1,1,1)
(3,1,1,1,1,1,1)
(2,1,1,1,1,1,1,1)
(1,1,1,1,1,1,1,1,1)
Including half-steps gives
A359893.
The median statistic is ranked by
A360005(n)/2.
A240219 counts partitions w/ the same mean as median, complement
A359894.
-
Table[Length[Select[IntegerPartitions[n],Median[#]==k&]],{n,15},{k,n}]
A237984
Number of partitions of n whose mean is a part.
Original entry on oeis.org
1, 2, 2, 3, 2, 5, 2, 6, 5, 8, 2, 21, 2, 14, 22, 30, 2, 61, 2, 86, 67, 45, 2, 283, 66, 80, 197, 340, 2, 766, 2, 663, 543, 234, 703, 2532, 2, 388, 1395, 4029, 2, 4688, 2, 4476, 7032, 1005, 2, 17883, 2434, 9713, 7684, 14472, 2, 25348, 17562, 37829, 16786, 3721
Offset: 1
a(6) counts these partitions: 6, 33, 321, 222, 111111.
From _Gus Wiseman_, Sep 14 2019: (Start)
The a(1) = 1 through a(10) = 8 partitions (A = 10):
1 2 3 4 5 6 7 8 9 A
11 111 22 11111 33 1111111 44 333 55
1111 222 2222 432 22222
321 3221 531 32221
111111 4211 111111111 33211
11111111 42211
52111
1111111111
(End)
The Heinz numbers of these partitions are
A327473.
A similar sequence for subsets is
A065795.
Partitions without their mean are
A327472.
-
Table[Count[IntegerPartitions[n], p_ /; MemberQ[p, Mean[p]]], {n, 40}]
-
from sympy.utilities.iterables import partitions
def A237984(n): return sum(1 for s,p in partitions(n,size=True) if not n%s and n//s in p) # Chai Wah Wu, Sep 21 2023
A102627
Number of partitions of n into distinct parts in which the number of parts divides n.
Original entry on oeis.org
1, 1, 1, 2, 1, 4, 1, 4, 4, 5, 1, 15, 1, 7, 14, 17, 1, 28, 1, 40, 28, 11, 1, 99, 31, 13, 49, 99, 1, 186, 1, 152, 76, 17, 208, 425, 1, 19, 109, 699, 1, 584, 1, 433, 823, 23, 1, 1625, 437, 1140, 193, 746, 1, 2003, 1748, 2749, 244, 29, 1, 7404, 1, 31, 4158, 3258, 3766, 6307, 1
Offset: 1
From _Gus Wiseman_, Sep 24 2019: (Start)
The a(1) = 1 through a(12) = 15 strict integer partitions whose average is an integer (A = 10, B = 11, C = 12):
(1) (2) (3) (4) (5) (6) (7) (8) (9) (A) (B) (C)
(31) (42) (53) (432) (64) (75)
(51) (62) (531) (73) (84)
(321) (71) (621) (82) (93)
(91) (A2)
(B1)
(543)
(642)
(651)
(732)
(741)
(831)
(921)
(5421)
(6321)
(End)
The BI-numbers of these partitions are given by
A326669 (numbers whose binary indices have integer mean).
Strict partitions with integer geometric mean are
A326625.
Strict partitions whose maximum divides their sum are
A326850.
-
a:= proc(m) option remember; local b; b:=
proc(n, i, t) option remember; `if`(i*(i+1)/2Alois P. Heinz, Sep 25 2019
-
npdp[n_]:=Count[Select[IntegerPartitions[n],Length[#]==Length[ Union[ #]]&], ?(Divisible[n,Length[#]]&)]; Array[npdp,70] (* _Harvey P. Dale, Feb 12 2016 *)
a[m_] := a[m] = Module[{b}, b[n_, i_, t_] := b[n, i, t] = If[i(i+1)/2 < n, 0, If[n == 0, If[Mod[m, t] == 0, 1, 0], b[n, i - 1, t] + b[n - i, Min[n - i, i - 1], t + 1]]]; If[PrimeQ[m], 1, b[m, m, 0]]];
Array[a, 100] (* Jean-François Alcover, May 21 2021, after Alois P. Heinz *)
A327482
Irregular triangle read by rows where T(n,k) is the number of integer partitions of n with mean d = A027750(n, k).
Original entry on oeis.org
1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 3, 3, 1, 1, 1, 1, 5, 4, 1, 1, 7, 1, 1, 7, 5, 1, 1, 1, 1, 11, 15, 12, 6, 1, 1, 1, 1, 15, 7, 1, 1, 30, 19, 1, 1, 22, 34, 8, 1, 1, 1, 1, 30, 58, 27, 9, 1, 1, 1, 1, 42, 84, 64, 10, 1, 1, 105, 37, 1, 1, 56, 11, 1
Offset: 1
Triangle begins:
1
1 1
1 1
1 2 1
1 1
1 3 3 1
1 1
1 5 4 1
1 7 1
1 7 5 1
1 1
1 11 15 12 6 1
1 1
1 15 7 1
1 30 19 1
1 22 34 8 1
The version for subsets is
A327481.
-
Table[Length[Select[IntegerPartitions[n],Mean[#]==d&]],{n,20},{d,Divisors[n]}]
A327473
Heinz numbers of integer partitions whose mean A326567/A326568 is a part.
Original entry on oeis.org
2, 3, 4, 5, 7, 8, 9, 11, 13, 16, 17, 19, 23, 25, 27, 29, 30, 31, 32, 37, 41, 43, 47, 49, 53, 59, 61, 64, 67, 71, 73, 79, 81, 83, 84, 89, 90, 97, 101, 103, 105, 107, 109, 110, 113, 121, 125, 127, 128, 131, 137, 139, 149, 151, 157, 163, 167, 169, 173, 179, 181
Offset: 1
The sequence of terms together with their prime indices begins:
2: {1}
3: {2}
4: {1,1}
5: {3}
7: {4}
8: {1,1,1}
9: {2,2}
11: {5}
13: {6}
16: {1,1,1,1}
17: {7}
19: {8}
23: {9}
25: {3,3}
27: {2,2,2}
29: {10}
30: {1,2,3}
31: {11}
32: {1,1,1,1,1}
37: {12}
The enumeration of these partitions by sum is given by
A237984.
Subsets whose mean is a part are
A065795.
Numbers whose binary indices include their mean are
A327478.
-
primeMS[n_]:=If[n==1,{},Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]];
Select[Range[100],MemberQ[primeMS[#],Mean[primeMS[#]]]&]
A359902
Triangle read by rows where T(n,k) is the number of odd-length integer partitions of n with median k.
Original entry on oeis.org
1, 0, 1, 1, 0, 1, 1, 0, 0, 1, 2, 1, 0, 0, 1, 2, 2, 0, 0, 0, 1, 4, 2, 1, 0, 0, 0, 1, 4, 3, 2, 0, 0, 0, 0, 1, 7, 4, 3, 1, 0, 0, 0, 0, 1, 8, 6, 3, 2, 0, 0, 0, 0, 0, 1, 12, 8, 4, 3, 1, 0, 0, 0, 0, 0, 1, 14, 11, 5, 4, 2, 0, 0, 0, 0, 0, 0, 1
Offset: 1
Triangle begins:
1
0 1
1 0 1
1 0 0 1
2 1 0 0 1
2 2 0 0 0 1
4 2 1 0 0 0 1
4 3 2 0 0 0 0 1
7 4 3 1 0 0 0 0 1
8 6 3 2 0 0 0 0 0 1
12 8 4 3 1 0 0 0 0 0 1
14 11 5 4 2 0 0 0 0 0 0 1
21 14 8 4 3 1 0 0 0 0 0 0 1
24 20 10 5 4 2 0 0 0 0 0 0 0 1
34 25 15 6 5 3 1 0 0 0 0 0 0 0 1
For example, row n = 9 counts the following partitions:
(7,1,1) (5,2,2) (3,3,3) (4,4,1) . . . . (9)
(3,3,1,1,1) (6,2,1) (4,3,2)
(4,2,1,1,1) (2,2,2,2,1) (5,3,1)
(5,1,1,1,1) (3,2,2,1,1)
(2,2,1,1,1,1,1)
(3,1,1,1,1,1,1)
(1,1,1,1,1,1,1,1,1)
The median statistic is ranked by
A360005(n)/2.
A240219 counts partitions w/ the same mean as median, complement
A359894.
-
Table[Length[Select[IntegerPartitions[n],OddQ[Length[#]]&&Median[#]==k&]],{n,15},{k,n}]
A307683
Number of partitions of n having a non-integer median.
Original entry on oeis.org
0, 0, 1, 0, 2, 1, 4, 1, 7, 5, 11, 8, 18, 17, 31, 28, 47, 51, 75, 81, 119, 134, 181, 206, 277, 323, 420, 488, 623, 737, 922, 1084, 1352, 1597, 1960, 2313, 2819, 3330, 4029, 4743, 5704, 6722, 8030, 9434, 11234, 13175, 15601, 18262, 21552, 25184, 29612, 34518
Offset: 1
a(7) counts these 4 partitions: [6,1], [5,2], [4,3], [3,2,1,1].
Cf.
A000016,
A051293,
A067538,
A082550,
A240219,
A240850,
A316413,
A326567/
A326568,
A327475,
A359897,
A360005.
Showing 1-10 of 186 results.
Comments