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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A238312 Square row sums of the table A072233 (A008284).

Original entry on oeis.org

1, 1, 2, 3, 7, 11, 25, 41, 82, 142, 260, 436, 785, 1287, 2199, 3592, 5959, 9511, 15453, 24268, 38565, 59838, 93232, 142589, 219089, 330848, 500658, 748140, 1117856, 1651987, 2441484, 3572470, 5223653, 7576447, 10971112, 15775735, 22649645, 32307553, 46001087, 65138447, 92045412
Offset: 0

Views

Author

Emanuele Munarini, Feb 24 2014

Keywords

Crossrefs

Programs

  • Mathematica
    pnkList[n_] := Table[Length[IntegerPartitions[n, {k}]], {k, 0, n}]
    Table[Total[Map[#^2 &, pnkList[n]]], {n, 0, 40}]

Formula

a(n) = Sum_{k=0..n} p(n,k)^2, where p(n,k) is the number of partitions of n into k positive parts (A072233, A008284).

A325514 Heinz number of row n of the triangle of partition numbers A008284.

Original entry on oeis.org

2, 2, 4, 8, 24, 72, 600, 4200, 101640, 2042040, 107869080, 6435365640, 644779672680, 62219208188280, 14408598135902520, 3195700205016233640, 1246437353286578234760, 527744165981695537415640, 417665868515500206974318760, 314096677106179199154141208440
Offset: 0

Views

Author

Gus Wiseman, May 07 2019

Keywords

Comments

The Heinz number of a positive integer sequence (y_1,...,y_k) is prime(y_1)*...*prime(y_k).

Examples

			The sequence of terms together with their prime indices begins:
             2: {1}
             2: {1}
             4: {1,1}
             8: {1,1,1}
            24: {1,1,1,2}
            72: {1,1,1,2,2}
           600: {1,1,1,2,3,3}
          4200: {1,1,1,2,3,3,4}
        101640: {1,1,1,2,3,4,5,5}
       2042040: {1,1,1,2,3,4,5,6,7}
     107869080: {1,1,1,2,3,5,5,7,8,9}
    6435365640: {1,1,1,2,3,5,5,7,10,10,11}
  644779672680: {1,1,1,2,3,5,6,7,11,12,13,15}
		

Crossrefs

Programs

  • Mathematica
    Times@@@Table[If[n>0&&k==0,1,Prime[Length[IntegerPartitions[n,{k}]]]],{n,0,20},{k,0,n}]

Formula

A001221(a(n)) = A325512(n).
A061395(a(n)) = A002569(n).
A056239(a(n)) = A000041(n).

A327028 T(n, k) = k! * Sum_{d|n} phi(d) * A008284(n/d, k) for n >= 1, T(0, k) = 0^k. Triangle read by rows for 0 <= k <= n.

Original entry on oeis.org

1, 0, 1, 0, 2, 2, 0, 3, 2, 6, 0, 4, 6, 6, 24, 0, 5, 4, 12, 24, 120, 0, 6, 12, 24, 48, 120, 720, 0, 7, 6, 24, 72, 240, 720, 5040, 0, 8, 16, 36, 144, 360, 1440, 5040, 40320, 0, 9, 12, 54, 144, 600, 2160, 10080, 40320, 362880
Offset: 0

Views

Author

Peter Luschny, Aug 20 2019

Keywords

Examples

			[0] 1
[1] 0, 1
[2] 0, 2,  2
[3] 0, 3,  2,  6
[4] 0, 4,  6,  6,  24
[5] 0, 5,  4, 12,  24, 120
[6] 0, 6, 12, 24,  48, 120,  720
[7] 0, 7,  6, 24,  72, 240,  720,  5040
[8] 0, 8, 16, 36, 144, 360, 1440,  5040, 40320
[9] 0, 9, 12, 54, 144, 600, 2160, 10080, 40320, 362880
		

Crossrefs

Cf. A008284, A318144, A000142 (main diagonal), A327025 (row sums), A327029.

Programs

  • Maple
    A327028 := (n,k) -> `if`(n=0, 1, k!*add(phi(d)*A008284(n/d, k), d = divisors(n))):
    seq(seq(A327028(n, k), k=0..n), n=0..9);
  • Mathematica
    A327028[0 , k_] := 1;
    A327028[n_, k_] := DivisorSum[n, EulerPhi[#] A318144[n/#, k] (-1)^k &];
    Table[A327028[n, k], {n, 0,  9}, {k, 0,  n}] // Flatten
  • SageMath
    # uses[DivisorTriangle from A327029]
    from sage.combinat.partition import number_of_partitions_length
    def A318144Abs(n, k): return number_of_partitions_length(n, k)*factorial(k)
    DivisorTriangle(euler_phi, A318144Abs, 10)

A039808 Shifts left under transform T where Ta is product of Partition Triangle A008284 with a.

Original entry on oeis.org

1, 1, 2, 4, 9, 20, 47, 109, 258, 609, 1447, 3434, 8175, 19449, 46327, 110330, 262882, 626317, 1492515, 3556540, 8475679, 20198343, 48136276, 114716767, 273393363, 651550405, 1552783297, 3700609736, 8819356189
Offset: 1

Views

Author

Christian G. Bower, Feb 15 1999

Keywords

Crossrefs

Formula

G.f.: x + x * Sum_{n>=1} a(n) * x^n / Product_{j=1..n} (1 - x^j). - Ilya Gutkovskiy, Jul 22 2021

A050302 Matrix 8th power of partition triangle A008284.

Original entry on oeis.org

1, 8, 1, 36, 8, 1, 148, 44, 8, 1, 498, 184, 44, 8, 1, 1590, 682, 192, 44, 8, 1, 4586, 2236, 718, 192, 44, 8, 1, 12644, 6822, 2420, 726, 192, 44, 8, 1, 32775, 19346, 7476, 2456, 726, 192, 44, 8, 1, 81901, 52177, 21646, 7660, 2464, 726, 192, 44, 8, 1, 196085
Offset: 1

Views

Author

Christian G. Bower, Aug 15 1999

Keywords

Examples

			1; 8,1; 36,8,1; 148,44,8,1; ...
		

Crossrefs

Cf. A038497, A038498, A039805-A039807. A050301-A050304. a(n, 1) = A024208(n) (first column).

A055889 CIK transform of partition triangle A008284.

Original entry on oeis.org

1, 1, 2, 1, 2, 3, 1, 4, 4, 5, 1, 4, 8, 8, 7, 1, 6, 13, 19, 16, 13, 1, 6, 18, 32, 40, 32, 19, 1, 8, 24, 56, 80, 90, 64, 35, 1, 8, 33, 80, 148, 196, 192, 128, 59, 1, 10, 40, 120, 247, 396, 464, 420, 256, 107, 1, 10, 50, 162, 392, 712, 1008, 1088, 896, 512, 187, 1, 12, 61
Offset: 1

Views

Author

Christian G. Bower, Jun 09 2000

Keywords

Examples

			1; 1,2; 1,2,3; 1,4,4,5; 1,4,8,8,7; ...
		

Crossrefs

Row sums give A055890.

A181845 Triangle read by rows: T(n,k) = max_{c in P(n,n-k+1)} lcm(c) where P(n,m) = A008284(n,m) is the number of partitions of n into m parts.

Original entry on oeis.org

1, 1, 2, 1, 2, 3, 1, 2, 3, 4, 1, 2, 3, 6, 5, 1, 2, 3, 6, 5, 6, 1, 2, 3, 6, 6, 12, 7, 1, 2, 3, 6, 6, 12, 15, 8, 1, 2, 3, 6, 6, 12, 15, 20, 9, 1, 2, 3, 6, 6, 12, 15, 30, 21, 10, 1, 2, 3, 6, 6, 12, 15, 30, 21, 30, 11, 1, 2, 3, 6, 6, 12, 15, 30, 30, 60, 35, 12
Offset: 1

Views

Author

Peter Luschny, Dec 07 2010

Keywords

Comments

See A181842 for the definition of 'partition'. T(n,k) is also the triangle read by rows: T(n,k) = max_{c in C(n,n-k+1)} lcm(c) where C(n,m) is the set of all m-tuples of positive integers whose elements sum to n where the C(n,k) = A007318(n-1,k-1) are called compositions of n of size k.

Examples

			[1]   1
[2]   1   2
[3]   1   2   3
[4]   1   2   3   4
[5]   1   2   3   6   5
[6]   1   2   3   6   5   6
[7]   1   2   3   6   6   12   7
[8]   1   2   3   6   6   12   15   8
[9]   1   2   3   6   6   12   15   20   9
		

Crossrefs

Programs

  • Maple
    with(combstruct):
    a181845_row := proc(n) local k,L,l,R,part;
    R := NULL;
    for k from 1 to n do
       L := 0;
       part := iterstructs(Partition(n),size=n-k+1):
    # alternatively (but slower)
    # part := iterstructs(Composition(n), size=n-k+1):
       while not finished(part) do
          l := nextstruct(part);
          L := max(L,ilcm(op(l)));
       od;
       R := R,L;
    od;
    R end:
  • PARI
    Row(n)={my(v=vector(n)); forpart(p=n, my(i=#p); v[i]=max(v[i], lcm(Vec(p)))); Vecrev(v)}
    { for(n=1, 10, print(Row(n))) } \\ Andrew Howroyd, Apr 20 2021

Extensions

Terms a(56) and beyond from Andrew Howroyd, Apr 20 2021

A238313 Alternating square row sums of the table A072233 (A008284).

Original entry on oeis.org

1, 1, 0, 1, 3, 1, 3, 3, 10, 18, 12, 26, 39, 57, 59, 116, 201, 219, 325, 416, 625, 810, 1074, 1447, 2345, 3078, 3530, 5084, 6790, 9063, 11674, 15580, 20887, 27537, 33640, 45065, 61297, 76883, 96889, 126243, 169268, 210005, 262068, 337445, 438197, 552346, 686794, 865904, 1128611, 1407533, 1732572
Offset: 0

Views

Author

Emanuele Munarini, Feb 24 2014

Keywords

Crossrefs

Programs

  • Mathematica
    pnkList[n_] := Table[Length[IntegerPartitions[n, {k}]], {k,0,n}]
    Table[Total[Table[(-1)^(n-k),{k,0,n}] Map[#^2 &, pnkList[n]]], {n,0,50}]

Formula

a(n) = sum((-1)^(n-k)*p(n,k)^2,k=0..n), where p(n,k) is the number of partitions of n into k positive parts (A072233, A008284).

A238314 Binomial transform of the squared rows of the table A072233 (A008284).

Original entry on oeis.org

1, 1, 3, 7, 33, 91, 388, 1163, 4231, 13297, 44694, 136621, 444535, 1335335, 4149785, 12327698, 37154245, 108185961, 318923590, 913506701, 2633793550, 7443298426, 21073435606, 58715695683, 163805615535, 450730653566, 1239947467778, 3374934052348
Offset: 0

Views

Author

Emanuele Munarini, Feb 24 2014

Keywords

Crossrefs

Programs

  • Mathematica
    pnkList[n_] := Table[Length[IntegerPartitions[n, {k}]], {k, 0, n}]
    Table[Total[Table[Binomial[n,k],{k,0,n}] Map[#^2 &, pnkList[n]]], {n,0,40}]

Formula

a(n) = sum(binomial(n,k)*p(n,k)^2,k=0..n), where p(n,k) is the number of partitions of n into k positive parts (A072233, A008284).

A327025 a(n) = Sum_{k=0..n} k! * Sum_{d|n} phi(d) * A008284(n/d, k).

Original entry on oeis.org

1, 1, 4, 11, 40, 165, 930, 6109, 47364, 416259, 4092332, 44424105, 527512456, 6798907261, 94504292830, 1408973416983, 22426222792568, 379522092608193, 6804315178122972, 128828842646944153, 2568533750232696472, 53788282243854348683, 1180357162840669081094
Offset: 0

Views

Author

Peter Luschny, Aug 23 2019

Keywords

Crossrefs

Row sums of A327028.
Previous Showing 21-30 of 579 results. Next