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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A325197 Heinz numbers of integer partitions such that the difference between the length of the minimal triangular partition containing and the maximal triangular partition contained in the Young diagram is 2.

Original entry on oeis.org

5, 8, 14, 21, 24, 25, 27, 28, 35, 36, 40, 54, 56, 66, 98, 99, 110, 120, 125, 132, 135, 147, 154, 165, 168, 175, 180, 189, 196, 198, 200, 220, 225, 231, 245, 250, 252, 264, 270, 275, 280, 297, 300, 308, 375, 378, 385, 390, 392, 396, 440, 450, 500, 546, 585, 594
Offset: 1

Views

Author

Gus Wiseman, Apr 11 2019

Keywords

Comments

The enumeration of these partitions by sum is given by A325199.

Examples

			The sequence of terms together with their prime indices begins:
    5: {3}
    8: {1,1,1}
   14: {1,4}
   21: {2,4}
   24: {1,1,1,2}
   25: {3,3}
   27: {2,2,2}
   28: {1,1,4}
   35: {3,4}
   36: {1,1,2,2}
   40: {1,1,1,3}
   54: {1,2,2,2}
   56: {1,1,1,4}
   66: {1,2,5}
   98: {1,4,4}
   99: {2,2,5}
  110: {1,3,5}
  120: {1,1,1,2,3}
  125: {3,3,3}
  132: {1,1,2,5}
		

Crossrefs

Programs

  • Mathematica
    primeptn[n_]:=If[n==1,{},Reverse[Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]]];
    otb[ptn_]:=Min@@MapIndexed[#1+#2[[1]]-1&,Append[ptn,0]];
    otbmax[ptn_]:=Max@@MapIndexed[#1+#2[[1]]-1&,Append[ptn,0]];
    Select[Range[1000],otbmax[primeptn[#]]-otb[primeptn[#]]==2&]

A325227 Regular triangle read by rows where T(n,k) is the number of integer partitions of n such that the lesser of the maximum part and the number of parts is k.

Original entry on oeis.org

0, 0, 1, 0, 2, 0, 0, 2, 1, 0, 0, 2, 3, 0, 0, 0, 2, 4, 1, 0, 0, 0, 2, 6, 3, 0, 0, 0, 0, 2, 6, 6, 1, 0, 0, 0, 0, 2, 8, 9, 3, 0, 0, 0, 0, 0, 2, 8, 13, 6, 1, 0, 0, 0, 0, 0, 2, 10, 16, 11, 3, 0, 0, 0, 0, 0, 0, 2, 10, 20, 17, 6, 1, 0, 0, 0, 0, 0, 0
Offset: 1

Views

Author

Gus Wiseman, Apr 12 2019

Keywords

Examples

			Triangle begins:
  1
  2  0
  2  1  0
  2  3  0  0
  2  4  1  0  0
  2  6  3  0  0  0
  2  6  6  1  0  0  0
  2  8  9  3  0  0  0  0
  2  8 13  6  1  0  0  0  0
  2 10 16 11  3  0  0  0  0  0
  2 10 20 17  6  1  0  0  0  0  0
  2 12 24 25 11  3  0  0  0  0  0  0
  2 12 28 33 19  6  1  0  0  0  0  0  0
  2 14 32 44 29 11  3  0  0  0  0  0  0  0
  2 14 38 53 43 19  6  1  0  0  0  0  0  0  0
Row n = 9 counts the following partitions:
  (9)          (54)        (333)      (4221)    (51111)
  (111111111)  (63)        (432)      (4311)
               (72)        (441)      (5211)
               (81)        (522)      (6111)
               (22221)     (531)      (42111)
               (222111)    (621)      (411111)
               (2211111)   (711)
               (21111111)  (3222)
                           (3321)
                           (32211)
                           (33111)
                           (321111)
                           (3111111)
		

Crossrefs

Programs

  • Mathematica
    Table[Length[Select[IntegerPartitions[n],Min[Length[#],Max[#]]==k&]],{n,15},{k,n}]

A325193 Number of integer partitions whose sum plus co-rank is n, where co-rank is maximum of length and largest part.

Original entry on oeis.org

1, 0, 1, 0, 2, 1, 3, 2, 5, 5, 8, 8, 14, 14, 22, 24, 35, 39, 54, 62, 84, 97, 127, 148, 192, 224, 284, 334, 418, 492, 610, 716, 880, 1035, 1259, 1480, 1790, 2100, 2522, 2958, 3533, 4135, 4916, 5742, 6798, 7928, 9344, 10878, 12778, 14846, 17378, 20156, 23520
Offset: 0

Views

Author

Gus Wiseman, Apr 12 2019

Keywords

Examples

			The a(4) = 2 through a(12) = 14 partitions:
  (2)   (21)  (3)    (31)   (4)     (33)    (5)      (43)     (6)
  (11)        (22)   (211)  (32)    (41)    (42)     (51)     (44)
              (111)         (221)   (222)   (322)    (332)    (52)
                            (311)   (321)   (331)    (421)    (333)
                            (1111)  (2111)  (411)    (2221)   (422)
                                            (2211)   (3211)   (431)
                                            (3111)   (4111)   (511)
                                            (11111)  (21111)  (2222)
                                                              (3221)
                                                              (3311)
                                                              (4211)
                                                              (22111)
                                                              (31111)
                                                              (111111)
		

Crossrefs

Programs

  • Mathematica
    Table[Sum[Length[Select[IntegerPartitions[k],Max[Length[#],Max[#]]==n-k&]],{k,0,n}],{n,0,30}]

A325199 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 2.

Original entry on oeis.org

0, 0, 0, 2, 0, 2, 6, 3, 2, 9, 15, 12, 6, 12, 27, 38, 34, 22, 20, 43, 74, 94, 90, 67, 48, 69, 130, 194, 232, 230, 187, 132, 129, 218, 364, 497, 576, 578, 498, 367, 290, 378, 642, 977, 1264, 1435, 1448, 1290, 1000, 735, 728
Offset: 0

Views

Author

Gus Wiseman, Apr 11 2019

Keywords

Comments

The Heinz numbers of these partitions are given by A325197.

Examples

			The a(3) = 2 through a(10) = 15 partitions (empty columns not shown):
  (3)    (41)    (33)    (43)    (521)    (333)    (433)
  (111)  (2111)  (42)    (2221)  (32111)  (441)    (442)
                 (222)   (4111)           (522)    (532)
                 (411)                    (531)    (541)
                 (2211)                   (3222)   (3322)
                 (3111)                   (5211)   (3331)
                                          (32211)  (4222)
                                          (33111)  (4411)
                                          (42111)  (5221)
                                                   (5311)
                                                   (32221)
                                                   (33211)
                                                   (42211)
                                                   (43111)
                                                   (52111)
		

Crossrefs

Programs

  • Mathematica
    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[#]==2&]],{n,0,30}]

A368986 a(n) = sum of the origin-to-boundary graph-distances of all partitions of n.

Original entry on oeis.org

0, 1, 2, 4, 8, 12, 21, 32, 50, 73, 107, 152, 219, 302, 419, 567, 771, 1027, 1374, 1806, 2375, 3083, 3999, 5136, 6597, 8398, 10676, 13477, 16981, 21260, 26584, 33057, 41049, 50738, 62605, 76930, 94374, 115330, 140704, 171106, 207732, 251460, 303919, 366335, 440880, 529298
Offset: 0

Views

Author

Andrew Howroyd, Jan 12 2024

Keywords

Comments

The origin-to-boundary graph-distance (see A325188) is the side length of the maximum triangular partition contained inside the Ferrer's diagram of the partition. a(n) is the sum of the side lengths over all partitions of n.

Crossrefs

Programs

  • PARI
    a(n)={my(s=0); forpart(p=n, my(w=#p); for(i=1, #p, w=min(w, #p-i+p[i])); s += w); s}

Formula

a(n) = Sum_{k=1..n} k*A325188(n,k).
Previous Showing 11-15 of 15 results.