A238867
Number of partitions of n where the difference between consecutive parts is at most 7.
Original entry on oeis.org
1, 1, 2, 3, 5, 7, 11, 15, 22, 30, 41, 54, 73, 95, 125, 162, 210, 268, 344, 434, 549, 688, 861, 1069, 1328, 1637, 2016, 2472, 3023, 3682, 4479, 5424, 6558, 7905, 9508, 11404, 13657, 16307, 19440, 23123, 27454, 32526, 38479, 45424, 53545, 63006, 74024, 86824, 101701, 118931, 138899, 161983, 188656, 219419, 254895, 295709
Offset: 0
Sequences "number of partitions with max diff d":
A000005 (d=0, for n>=1),
A034296 (d=1),
A224956 (d=2),
A238863 (d=3),
A238864 (d=4),
A238865 (d=5),
A238866 (d=6), this sequence,
A238868 (d=8),
A238869 (d=9),
A000041 (d --> infinity).
-
b:= proc(n, i) option remember; `if`(n=0, 1, `if`(i<1, 0,
add(b(n-i*j, i-1), j=0..min(7, n/i))))
end:
g:= proc(n, i) option remember; `if`(n=0, 1, `if`(i<1, 0,
add(b(n-i*j, i-1), j=1..n/i)))
end:
a:= n-> add(g(n, k), k=0..n):
seq(a(n), n=0..60); # Alois P. Heinz, Mar 09 2014
-
b[n_, i_] := b[n, i] = If[n == 0, 1, If[i<1, 0, Sum[b[n - i*j, i-1], {j, 0, Min[7, n/i]}]]]; g[n_, i_] := g[n, i] = If[n == 0, 1, If[i<1, 0, Sum[b[n - i*j, i-1], {j, 1, n/i}]]]; a[n_] := Sum[g[n, k], {k, 0, n}]; Table[a[n], {n, 0, 60}] (* Jean-François Alcover, Feb 18 2015, after Alois P. Heinz *)
-
N=66; q = 'q + O('q^N);
Vec( 1 + sum(k=1, N, q^k/(1-q^k) * prod(i=1,k-1, (1-q^(8*i))/(1-q^i) ) ) )
A238868
Number of partitions of n where the difference between consecutive parts is at most 8.
Original entry on oeis.org
1, 1, 2, 3, 5, 7, 11, 15, 22, 30, 42, 55, 75, 97, 129, 166, 217, 276, 356, 449, 572, 715, 900, 1117, 1393, 1717, 2123, 2601, 3193, 3889, 4744, 5748, 6970, 8404, 10135, 12165, 14600, 17448, 20845, 24813, 29522, 35009, 41491, 49031, 57900, 68195, 80258, 94234, 110553, 129421, 151382, 176724, 206132, 240002, 279195, 324255
Offset: 0
Sequences "number of partitions with max diff d":
A000005 (d=0, for n>=1),
A034296 (d=1),
A224956 (d=2),
A238863 (d=3),
A238864 (d=4),
A238865 (d=5),
A238866 (d=6),
A238867 (d=7), this sequence,
A238869 (d=9),
A000041 (d --> infinity).
-
b:= proc(n, i) option remember; `if`(n=0, 1, `if`(i<1, 0,
add(b(n-i*j, i-1), j=0..min(8, n/i))))
end:
g:= proc(n, i) option remember; `if`(n=0, 1, `if`(i<1, 0,
add(b(n-i*j, i-1), j=1..n/i)))
end:
a:= n-> add(g(n, k), k=0..n):
seq(a(n), n=0..60); # Alois P. Heinz, Mar 09 2014
-
b[n_, i_] := b[n, i] = If[n == 0, 1, If[i<1, 0, Sum[b[n - i*j, i-1], {j, 0, Min[8, n/i]}]]]; g[n_, i_] := g[n, i] = If[n == 0, 1, If[i<1, 0, Sum[b[n - i*j, i-1], {j, 1, n/i}]]]; a[n_] := Sum[g[n, k], {k, 0, n}]; Table[a[n], {n, 0, 60}] (* Jean-François Alcover, Feb 18 2015, after Alois P. Heinz *)
-
N=66; q = 'q + O('q^N);
Vec( 1 + sum(k=1, N, q^k/(1-q^k) * prod(i=1,k-1, (1-q^(9*i))/(1-q^i) ) ) )
A238869
Number of partitions of n where the difference between consecutive parts is at most 9.
Original entry on oeis.org
1, 1, 2, 3, 5, 7, 11, 15, 22, 30, 42, 56, 76, 99, 131, 170, 221, 283, 364, 461, 586, 737, 926, 1154, 1439, 1779, 2199, 2703, 3317, 4051, 4942, 6001, 7278, 8796, 10610, 12760, 15323, 18344, 21928, 26148, 31127, 36971, 43848, 51890, 61321, 72327, 85183, 100149, 117588, 137827, 161343, 188583, 220139, 256607, 298761, 347360
Offset: 0
Sequences "number of partitions with max diff d":
A000005 (d=0, for n>=1),
A034296 (d=1),
A224956 (d=2),
A238863 (d=3),
A238864 (d=4),
A238865 (d=5),
A238866 (d=6),
A238867 (d=7),
A238868 (d=8), this sequence,
A000041 (d --> infinity).
-
b:= proc(n, i) option remember; `if`(n=0, 1, `if`(i<1, 0,
add(b(n-i*j, i-1), j=0..min(9, n/i))))
end:
g:= proc(n, i) option remember; `if`(n=0, 1, `if`(i<1, 0,
add(b(n-i*j, i-1), j=1..n/i)))
end:
a:= n-> add(g(n, k), k=0..n):
seq(a(n), n=0..60); # Alois P. Heinz, Mar 09 2014
-
b[n_, i_] := b[n, i] = If[n == 0, 1, If[i<1, 0, Sum[b[n - i*j, i-1], {j, 0, Min[9, n/i]}]]]; g[n_, i_] := g[n, i] = If[n == 0, 1, If[i<1, 0, Sum[b[n - i*j, i-1], {j, 1, n/i}]]]; a[n_] := Sum[g[n, k], {k, 0, n}]; Table[a[n], {n, 0, 60}] (* Jean-François Alcover, Feb 18 2015, after Alois P. Heinz *)
Table[Count[IntegerPartitions[n],?(Max[Abs[Differences[#]]]<10&)],{n,0,60}] (* _Harvey P. Dale, Nov 24 2024 *)
-
N=66; q = 'q + O('q^N);
Vec( 1 + sum(k=1, N, q^k/(1-q^k) * prod(i=1,k-1, (1-q^(10*i))/(1-q^i) ) ) )
A238354
Triangle T(n,k) read by rows: T(n,k) is the number of partitions of n (as weakly ascending list of parts) with minimal ascent k, n >= 0, 0 <= k <= n.
Original entry on oeis.org
1, 1, 0, 2, 0, 0, 2, 1, 0, 0, 4, 0, 1, 0, 0, 5, 1, 0, 1, 0, 0, 8, 1, 1, 0, 1, 0, 0, 11, 2, 0, 1, 0, 1, 0, 0, 17, 2, 1, 0, 1, 0, 1, 0, 0, 23, 3, 1, 1, 0, 1, 0, 1, 0, 0, 33, 4, 2, 0, 1, 0, 1, 0, 1, 0, 0, 45, 5, 2, 1, 0, 1, 0, 1, 0, 1, 0, 0, 63, 6, 3, 1, 1, 0, 1, 0, 1, 0, 1, 0, 0, 84, 8, 3, 2, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 114, 10, 4, 2, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0
Offset: 0
Triangle starts:
00: 1;
01: 1, 0;
02: 2, 0, 0;
03: 2, 1, 0, 0;
04: 4, 0, 1, 0, 0;
05: 5, 1, 0, 1, 0, 0;
06: 8, 1, 1, 0, 1, 0, 0;
07: 11, 2, 0, 1, 0, 1, 0, 0;
08: 17, 2, 1, 0, 1, 0, 1, 0, 0;
09: 23, 3, 1, 1, 0, 1, 0, 1, 0, 0;
10: 33, 4, 2, 0, 1, 0, 1, 0, 1, 0, 0;
11: 45, 5, 2, 1, 0, 1, 0, 1, 0, 1, 0, 0;
12: 63, 6, 3, 1, 1, 0, 1, 0, 1, 0, 1, 0, 0;
13: 84, 8, 3, 2, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0;
14: 114, 10, 4, 2, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0;
15: 150, 13, 4, 3, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0;
...
The 11 partitions of 6 together with their minimal ascents are:
01: [ 1 1 1 1 1 1 ] 0
02: [ 1 1 1 1 2 ] 0
03: [ 1 1 1 3 ] 0
04: [ 1 1 2 2 ] 0
05: [ 1 1 4 ] 0
06: [ 1 2 3 ] 1
07: [ 1 5 ] 4
08: [ 2 2 2 ] 0
09: [ 2 4 ] 2
10: [ 3 3 ] 0
11: [ 6 ] 0
There are 8 partitions of 6 with min ascent 0, 1 with min ascents 1, 2, and 4, giving row 6 of the triangle: 8, 1, 1, 0, 1, 0, 0.
Cf.
A238353 (partitions by maximal ascent).
-
b:= proc(n, i, t) option remember; `if`(n=0, 1/x, `if`(i<1, 0,
b(n, i-1, t)+`if`(i>n, 0, (p->`if`(t=0, p, add(coeff(
p, x, j)*x^`if`(j<0, t-i, min(j, t-i)),
j=-1..degree(p))))(b(n-i, i, i)))))
end:
T:= n->(p->seq(coeff(p, x, k)+`if`(k=0, 1, 0), k=0..n))(b(n$2, 0)):
seq(T(n), n=0..15);
-
b[n_, i_, t_] := b[n, i, t] = If[n == 0, 1/x, If[i<1, 0, b[n, i-1, t]+If[i>n, 0, Function[{p}, If[t == 0, p, Sum[Coefficient[p, x, j]*x^If[j<0, t-i, Min[j, t-i]], {j, -1, Exponent[p, x]}]]][b[n-i, i, i]]]]]; T[n_] := Function[{p}, Table[ Coefficient[p, x, k]+If[k == 0, 1, 0], {k, 0, n}]][b[n, n, 0]]; Table[T[n], {n, 0, 15}] // Flatten (* Jean-François Alcover, Jan 12 2015, translated from Maple *)
A251729
Number of gap-free but not complete compositions of n.
Original entry on oeis.org
0, 1, 1, 2, 3, 3, 6, 6, 14, 12, 27, 33, 58, 86, 134, 210, 323, 539, 810, 1371, 2044, 3510, 5263, 8927, 13702, 22870, 35821, 58750, 93343, 152236, 243244, 395078, 634342, 1027876, 1656543, 2676693, 4325727, 6982440, 11299457, 18232217, 29518334, 47641410
Offset: 1
a(6) = 3: [6], [3,3], [2,2,2].
a(7) = 6: [7], [3,4], [4,3], [2,2,3], [2,3,2], [3,2,2].
-
b:= proc(n, i, t) option remember; `if`(n=0, `if`(i=0, 0, t!),
`if`(i<1 or n add(b(n, i, 0), i=1..n):
seq(a(n), n=1..50);
-
b[n_, i_, t_] := b[n, i, t] = If[n == 0, If[i == 0, 0, t!], If[i < 1 || n < i, 0, Sum[b[n - i*j, i - 1, t + j]/j!, {j, 1, n/i}]]];
a[n_] := Sum[b[n, i, 0], {i, 1, n}];
Array[a, 50] (* Jean-François Alcover, Jan 25 2021, after Alois P. Heinz *)
A355528
Minimal difference between adjacent 0-prepended prime indices of n > 1.
Original entry on oeis.org
1, 2, 0, 3, 1, 4, 0, 0, 1, 5, 0, 6, 1, 1, 0, 7, 0, 8, 0, 2, 1, 9, 0, 0, 1, 0, 0, 10, 1, 11, 0, 2, 1, 1, 0, 12, 1, 2, 0, 13, 1, 14, 0, 0, 1, 15, 0, 0, 0, 2, 0, 16, 0, 2, 0, 2, 1, 17, 0, 18, 1, 0, 0, 3, 1, 19, 0, 2, 1, 20, 0, 21, 1, 0, 0, 1, 1, 22, 0, 0, 1, 23
Offset: 2
The 0-prepended prime indices of 9842 are {0,1,4,8,12}, with differences (1,3,4,4), so a(9842) = 1.
Crossrefs found in the link are not repeated here.
Positions of first appearances are 4 followed by
A000040.
A similar statistic is counted by
A238353.
A001522 counts partitions with a fixed point (unproved), ranked by
A352827.
Cf.
A064428,
A066312,
A091602,
A120944,
A238354,
A286470,
A325161,
A352822,
A355527,
A355531,
A355532.
-
primeMS[n_]:=If[n==1,{},Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]];
Table[Min@@Differences[Prepend[primeMS[n],0]],{n,2,100}]
A237665
Number of partitions of n such that the distinct terms arranged in increasing order form a string of two or more consecutive integers.
Original entry on oeis.org
0, 0, 0, 1, 1, 3, 3, 6, 6, 10, 11, 16, 17, 24, 27, 35, 39, 50, 57, 70, 79, 97, 111, 132, 150, 178, 204, 239, 271, 316, 361, 416, 472, 545, 618, 706, 800, 912, 1032, 1173, 1320, 1496, 1687, 1902, 2137, 2410, 2702, 3034, 3398, 3808, 4258, 4765, 5313, 5932, 6613
Offset: 0
The qualifying partitions of 8 are 332, 3221, 32111, 22211, 221111, 2111111, so that a(8) = 6. (The strings of distinct parts arranged in increasing order are 23, 123, 123, 12, 12, 12.)
-
b:= proc(n, i, t) option remember;
`if`(n=0 or i=1, `if`(n=0 and t=2 or n>0 and t>0, 1, 0),
`if`(i>n, 0, add(b(n-i*j, i-1, min(t+1, 2)), j=1..n/i)))
end:
a:= n-> add(b(n, i, 0), i=1..n):
seq(a(n), n=0..60); # Alois P. Heinz, Feb 15 2014
-
Map[Length[Select[Map[Differences[DeleteDuplicates[#]] &, IntegerPartitions[#]], (Table[-1, {Length[#]}] == # && # =!= \{}) &]] &, Range[55]] (* Peter J. C. Moses, Feb 09 2014 *)
b[n_, i_, t_] := b[n, i, t] = If[n==0 || i==1, If[n==0 && t==2 || n>0 && t > 0, 1, 0], If[i>n, 0, Sum[b[n-i*j, i-1, Min[t+1, 2]], {j, 1, n/i}]]]; a[n_] := Sum[b[n, i, 0], {i, 1, n}]; Table[a[n], {n, 0, 60}] (* Jean-François Alcover, Nov 17 2015, after Alois P. Heinz *)
A355527
Squarefree numbers having at least one pair of consecutive prime factors. Numbers n such that the minimal difference between adjacent prime indices of n is 1.
Original entry on oeis.org
6, 15, 30, 35, 42, 66, 70, 77, 78, 102, 105, 114, 138, 143, 154, 165, 174, 186, 195, 210, 221, 222, 231, 246, 255, 258, 282, 285, 286, 318, 323, 330, 345, 354, 366, 385, 390, 402, 426, 429, 435, 437, 438, 442, 455, 462, 465, 474, 498, 510, 534, 546, 555, 570
Offset: 1
The terms together with their prime indices begin:
6: {1,2}
15: {2,3}
30: {1,2,3}
35: {3,4}
42: {1,2,4}
66: {1,2,5}
70: {1,3,4}
77: {4,5}
78: {1,2,6}
102: {1,2,7}
105: {2,3,4}
114: {1,2,8}
138: {1,2,9}
143: {5,6}
154: {1,4,5}
165: {2,3,5}
174: {1,2,10}
186: {1,2,11}
195: {2,3,6}
210: {1,2,3,4}
Crossrefs found in the link are not repeated here.
For minimal difference <= 1 we have
A055932.
For maximal instead of minimal difference = 1 we have
A066312.
For minimal difference > 1 we have
A325160.
If zero is considered a prime index we get
A355530.
A001522 counts partitions with a fixed point (unproved), ranked by
A352827.
Cf.
A000005,
A000040,
A056239,
A120944,
A130091,
A238353,
A238354,
A286470,
A325161,
A352822,
A355526,
A355531.
-
primeMS[n_]:=If[n==1,{},Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]];
Select[Range[100],Min@@Differences[primeMS[#]]==1&]
A355523
Number of distinct differences between adjacent prime indices of n.
Original entry on oeis.org
0, 0, 0, 1, 0, 1, 0, 1, 1, 1, 0, 2, 0, 1, 1, 1, 0, 2, 0, 2, 1, 1, 0, 2, 1, 1, 1, 2, 0, 1, 0, 1, 1, 1, 1, 2, 0, 1, 1, 2, 0, 2, 0, 2, 2, 1, 0, 2, 1, 2, 1, 2, 0, 2, 1, 2, 1, 1, 0, 2, 0, 1, 2, 1, 1, 2, 0, 2, 1, 2, 0, 2, 0, 1, 2, 2, 1, 2, 0, 2, 1, 1, 0, 3, 1, 1, 1, 2, 0, 2, 1, 2, 1, 1, 1, 2, 0, 2, 2, 2, 0, 2, 0, 2, 1
Offset: 1
For example, the prime indices of 22770 are {1,2,2,3,5,9}, with differences (1,0,1,2,4), so a(22770) = 4.
Crossrefs found in the link are not repeated here.
A008578 gives the positions of 0's.
A287352 lists differences between 0-prepended prime indices.
A355534 lists augmented differences between prime indices.
A355536 lists differences between prime indices.
-
primeMS[n_]:=If[n==1,{},Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]];
Table[Length[Union[Differences[primeMS[n]]]],{n,1000}]
-
A355523(n) = if(1==n, 0, my(pis = apply(primepi,factor(n)[,1]), difs = vector(#pis-1, i, pis[i+1]-pis[i])); (#Set(difs)+!issquarefree(n))); \\ Antti Karttunen, Jan 20 2025
A342531
Triangle read by rows where T(n,k) is the number of strict integer partitions of n with maximal descent k, n >= 0, 0 <= k <= n.
Original entry on oeis.org
1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1, 1, 1, 0, 1, 0, 0, 1, 1, 1, 1, 0, 1, 0, 0, 1, 0, 2, 1, 1, 0, 1, 0, 0, 1, 2, 1, 1, 1, 1, 0, 1, 0, 0, 1, 1, 2, 2, 1, 1, 1, 0, 1, 0, 0, 1, 1, 2, 3, 1, 1, 1, 1, 0, 1, 0, 0
Offset: 0
Triangle begins:
1
1 0
1 0 0
1 1 0 0
1 0 1 0 0
1 1 0 1 0 0
1 1 1 0 1 0 0
1 1 1 1 0 1 0 0
1 0 2 1 1 0 1 0 0
1 2 1 1 1 1 0 1 0 0
1 1 2 2 1 1 1 0 1 0 0
1 1 2 3 1 1 1 1 0 1 0 0
1 1 3 2 3 1 1 1 1 0 1 0 0
1 1 3 3 3 2 1 1 1 1 0 1 0 0
1 1 3 4 3 3 2 1 1 1 1 0 1 0 0
1 3 3 4 4 3 2 2 1 1 1 1 0 1 0 0
1 0 5 5 5 4 3 2 2 1 1 1 1 0 1 0 0
1 1 4 7 5 5 4 2 2 2 1 1 1 1 0 1 0 0
1 2 5 6 7 6 4 4 2 2 2 1 1 1 1 0 1 0 0
1 1 5 9 7 7 6 4 3 2 2 2 1 1 1 1 0 1 0 0
1 1 6 9 9 7 8 5 4 3 2 2 2 1 1 1 1 0 1 0 0
Row n = 15 counts the following strict partitions (empty columns indicated by dots, A..F = 10..15):
F 87 753 96 762 A5 A41 B4 B31 C3 C21 D2 . E1 . .
654 6432 852 843 861 9321 A32
54321 6531 7431 951 942
7521 8421
A049980 counts strict partitions with equal differences.
A325325 counts partitions with distinct differences (ranking:
A325368).
A325545 counts compositions with distinct differences.
-
Table[Length[Select[IntegerPartitions[n],UnsameQ@@#&&If[Length[#]<=1,k==0,Max[Differences[Reverse[#]]]==k]&]],{n,0,15},{k,0,n}]
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