A366157 -id:A366157 - cp's OEIS frontend

A325189 Regular triangle read by rows where T(n,k) is the number of integer partitions of n with maximum origin-to-boundary graph-distance equal to k.

1, 0, 1, 0, 0, 2, 0, 0, 1, 2, 0, 0, 0, 3, 2, 0, 0, 0, 3, 2, 2, 0, 0, 0, 1, 6, 2, 2, 0, 0, 0, 0, 7, 4, 2, 2, 0, 0, 0, 0, 6, 8, 4, 2, 2, 0, 0, 0, 0, 4, 12, 6, 4, 2, 2, 0, 0, 0, 0, 1, 15, 12, 6, 4, 2, 2, 0, 0, 0, 0, 0, 17, 15, 10, 6, 4, 2, 2

Offset: 0

Gus Wiseman, Apr 11 2019

The maximum origin-to-boundary graph-distance of an integer partition is one plus the maximum number of unit steps East or South in the Young diagram that can be followed, starting from the upper-left square, to reach a boundary square in the lower-right quadrant. It is also the side-length of the minimum triangular partition containing the diagram.

			Triangle begins:
  1
  0  1
  0  0  2
  0  0  1  2
  0  0  0  3  2
  0  0  0  3  2  2
  0  0  0  1  6  2  2
  0  0  0  0  7  4  2  2
  0  0  0  0  6  8  4  2  2
  0  0  0  0  4 12  6  4  2  2
  0  0  0  0  1 15 12  6  4  2  2
  0  0  0  0  0 17 15 10  6  4  2  2
  0  0  0  0  0 14 23 16 10  6  4  2  2
  0  0  0  0  0 10 30 23 14 10  6  4  2  2
  0  0  0  0  0  5 39 29 24 14 10  6  4  2  2
  0  0  0  0  0  1 42 42 31 22 14 10  6  4  2  2
Row 9 counts the following partitions:
  (432)   (54)     (63)      (72)       (81)        (9)
  (3321)  (333)    (621)     (711)      (21111111)  (111111111)
  (4221)  (441)    (6111)    (2211111)
  (4311)  (522)    (222111)  (3111111)
          (531)    (321111)
          (3222)   (411111)
          (5211)
          (22221)
          (32211)
          (33111)
          (42111)
          (51111)

Andrew Howroyd, Table of n, a(n) for n = 0..1325 (rows 0..50)
Bridget Eileen Tenner, Reduced word manipulation: patterns and enumeration, J. Algebr. Comb. 46, No. 1, 189-217 (2017), table 1.
Tewodros Amdeberhan, George E. Andrews, and Cristina Ballantine, Hook length and symplectic content in partitions, arXiv:2205.07322 [math.CO], 2022.
Eric Weisstein's World of Mathematics, Graph Distance

Row sums are A000041. Column sums are A071724.

Cf. A065770, A096771, A115720, A115994, A139582, A325169, A325183, A325188, A325195, A325200, A366157.

otbmax[ptn_]:=Max@@MapIndexed[#1+#2[[1]]-1&,Append[ptn,0]];
Table[Length[Select[IntegerPartitions[n],otbmax[#]==k&]],{n,0,15},{k,0,n}]

row(n)={my(r=vector(n+1)); forpart(p=n, my(w=0); for(i=1, #p, w=max(w,#p-i+p[i])); r[w+1]++); r} \\ Andrew Howroyd, Jan 12 2024

Sum_{k=1..n} k*T(n,k) = A366157(n). - Andrew Howroyd, Jan 12 2024

A325200 Regular triangle read by rows where T(n,k) is the number of integer partitions of n such that the difference between the length of the minimal triangular partition containing and the maximal triangular partition contained in the Young diagram is k.

Original entry on oeis.org

1, 1, 0, 0, 2, 0, 1, 0, 2, 0, 0, 3, 0, 2, 0, 0, 3, 2, 0, 2, 0, 1, 0, 6, 2, 0, 2, 0, 0, 4, 3, 4, 2, 0, 2, 0, 0, 6, 2, 6, 4, 2, 0, 2, 0, 0, 4, 9, 5, 4, 4, 2, 0, 2, 0, 1, 0, 15, 6, 8, 4, 4, 2, 0, 2, 0, 0, 5, 12, 12, 9, 6, 4, 4, 2, 0, 2, 0, 0, 10, 6, 21, 10, 12, 6, 4, 4, 2, 0, 2, 0

Offset: 0

Gus Wiseman, Apr 11 2019

			Triangle begins:
  1
  1  0
  0  2  0
  1  0  2  0
  0  3  0  2  0
  0  3  2  0  2  0
  1  0  6  2  0  2  0
  0  4  3  4  2  0  2  0
  0  6  2  6  4  2  0  2  0
  0  4  9  5  4  4  2  0  2  0
  1  0 15  6  8  4  4  2  0  2  0
  0  5 12 12  9  6  4  4  2  0  2  0
  0 10  6 21 10 12  6  4  4  2  0  2  0
  0 10 12 20 18 13 10  6  4  4  2  0  2  0
  0  5 27 20 23 16 16 10  6  4  4  2  0  2  0
  1  0 38 22 32 22 19 14 10  6  4  4  2  0  2  0
  0  6 34 38 34 35 20 22 14 10  6  4  4  2  0  2  0
  0 15 22 57 44 40 34 23 20 14 10  6  4  4  2  0  2  0
  0 20 20 71 55 54 45 32 26 20 14 10  6  4  4  2  0  2  0
  0 15 43 70 71 66 60 44 35 24 20 14 10  6  4  4  2  0  2  0
  0  6 74 64 99 83 70 65 42 38 24 20 14 10  6  4  4  2  0  2  0
Row n = 9 counts the following partitions (empty columns not shown):
  (432)   (333)    (54)      (63)      (72)       (81)        (9)
  (3321)  (441)    (621)     (6111)    (711)      (21111111)  (111111111)
  (4221)  (522)    (22221)   (222111)  (2211111)
  (4311)  (531)    (51111)   (411111)  (3111111)
          (3222)   (321111)
          (5211)
          (32211)
          (33111)
          (42111)

Andrew Howroyd, Table of n, a(n) for n = 0..1325 (rows 0..50)
FindStat, St000380: Half the perimeter of the largest rectangle that fits inside the diagram of an integer partition
FindStat, St000384: The maximal part of the shifted composition of an integer partition
FindStat, St000783: The maximal number of occurrences of a colour in a proper colouring of a Ferrers diagram

Row sums are A000041. Column k = 1 is A325191. Column k = 2 is A325199.
T(n,k) = A325189(n,k) - A325188(n,k).
Cf. A046660, A065770, A071724, A243055, A325169, A325178, A325195, A325196, A325197, A366157, A368986.

otb[ptn_]:=Min@@MapIndexed[#1+#2[[1]]-1&,Append[ptn,0]];
otbmax[ptn_]:=Max@@MapIndexed[#1+#2[[1]]-1&,Append[ptn,0]];
Table[Length[Select[IntegerPartitions[n],otbmax[#]-otb[#]==k&]],{n,0,20},{k,0,n}]

row(n)={my(r=vector(n+1)); forpart(p=n, my(b=#p,c=0); for(i=1, #p, my(x=#p-i+p[i]); b=min(b,x); c=max(c,x)); r[c-b+1]++); r} \\ Andrew Howroyd, Jan 12 2024

Sum_{k=1..n} k*T(n,k) = A366157(n) - A368986(n). - Andrew Howroyd, Jan 13 2024

A366175 The number of lit cells in weakly decreasing partitions of n when light shines from the north west and only the first column is lit. Here partitions are represented from left to right by columns of cells.

Original entry on oeis.org

1, 2, 5, 7, 15, 22, 35, 54, 86, 115, 175, 248, 351, 480, 662, 890, 1229, 1622, 2154, 2820, 3718, 4814, 6269, 8048, 10303, 13086, 16648, 20998, 26540, 33196, 41509, 51607, 64086, 79162, 97769, 120213, 147587, 180401, 220173, 267697, 325211, 393778, 476237

Offset: 1

Arnold Knopfmacher, Oct 03 2023

nonn

A. Blecher, A. Knopfmacher, and M. E. Mays, Casting light on integer partitions, preprint.

Cf. A366069, A179862, A366157.

T[r_, s_] := If[s > r, 0, If[s == 0, 1, If[r == 1 && s == 1, q, If[r == 2 && s == 1, q*(1 + q), q^s*Sum[T[r - 1, i], {i, 0, s}]]]]]; nmax = 15; Rest[CoefficientList[Series[Sum[(r + 1)*q^(r + 1)*Sum[T[r, s], {s, 0, r}], {r, 0, nmax}], {q, 0, nmax}], q]] (* Vaclav Kotesovec, Oct 04 2023 *)

G.f.: Sum_{r>=0} (r+1)*q^(r+1)*T_q(r) where T_q(k) = Sum_{s=0..k} t(k,s) with t(r,s) = q^s*Sum_{i=0..s} t(r-1,i) and initial conditions t(1,1) = q; t(2,1) = q(1+q); t(r,0) = 1; t(r,s) = 0 for s>r.

a(14)-a(16) from Vaclav Kotesovec, Oct 04 2023

a(17)-a(43) from Alois P. Heinz, Oct 04 2023

A372768 The number of shaded cells in all compositions of n when light shines from the northwest. Here compositions are represented by stacked columns of adjacent cells.

Original entry on oeis.org

0, 1, 4, 13, 34, 85, 199, 454, 1011, 2220, 4813, 10351, 22104, 46948, 99266, 209113

Offset: 1

Michael Mays, May 12 2024

			For n=4, the composition 1+3 produces 3 shaded cells, 2+2 produces 1, 3+1 produces 2, 1+1+2 produces 1, 4 produces 6, and the others have no shaded cells, for a total of 13, so a(4) = 13.

A. Blecher, A. Knopfmacher, and M. E. Mays, Shade in compositions of integers, Journal of Integer Sequences, Vol. 27 (2024), Article 24.5.6.

Cf. A366157.

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A325189 Regular triangle read by rows where T(n,k) is the number of integer partitions of n with maximum origin-to-boundary graph-distance equal to k.

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A325200 Regular triangle read by rows where T(n,k) is the number of integer partitions of n such that the difference between the length of the minimal triangular partition containing and the maximal triangular partition contained in the Young diagram is k.

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A366175 The number of lit cells in weakly decreasing partitions of n when light shines from the north west and only the first column is lit. Here partitions are represented from left to right by columns of cells.

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A372768 The number of shaded cells in all compositions of n when light shines from the northwest. Here compositions are represented by stacked columns of adjacent cells.

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