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.

Showing 1-10 of 13 results. Next

A321884 Number A(n,k) of partitions of n into colored blocks of equal parts with colors from a set of size k; square array A(n,k), n>=0, k>=0, read by antidiagonals.

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 2, 2, 0, 1, 3, 4, 3, 0, 1, 4, 6, 8, 5, 0, 1, 5, 8, 15, 14, 7, 0, 1, 6, 10, 24, 27, 24, 11, 0, 1, 7, 12, 35, 44, 51, 40, 15, 0, 1, 8, 14, 48, 65, 88, 93, 64, 22, 0, 1, 9, 16, 63, 90, 135, 176, 159, 100, 30, 0, 1, 10, 18, 80, 119, 192, 295, 312, 264, 154, 42, 0
Offset: 0

Views

Author

Alois P. Heinz, Aug 27 2019

Keywords

Examples

			A(3,2) = 8: 3a, 3b, 2a1a, 2a1b, 2b1a, 2b1b, 111a, 111b.
Square array A(n,k) begins:
  1,  1,   1,   1,   1,   1,    1,    1,    1, ...
  0,  1,   2,   3,   4,   5,    6,    7,    8, ...
  0,  2,   4,   6,   8,  10,   12,   14,   16, ...
  0,  3,   8,  15,  24,  35,   48,   63,   80, ...
  0,  5,  14,  27,  44,  65,   90,  119,  152, ...
  0,  7,  24,  51,  88, 135,  192,  259,  336, ...
  0, 11,  40,  93, 176, 295,  456,  665,  928, ...
  0, 15,  64, 159, 312, 535,  840, 1239, 1744, ...
  0, 22, 100, 264, 544, 970, 1572, 2380, 3424, ...
		

Crossrefs

Columns k=0-4 give: A000007, A000041, A015128, A264686, A266821.
Main diagonal gives A321880.

Programs

  • Maple
    b:= proc(n, i, k) option remember; `if`(n=0, 1, `if`(i<1, 0, add(
          (t-> b(t, min(t, i-1), k))(n-i*j), j=1..n/i)*k+b(n, i-1, k)))
        end:
    A:= (n, k)-> b(n$2, k):
    seq(seq(A(n, d-n), n=0..d), d=0..14);
  • Mathematica
    b[n_, i_, k_] := b[n, i, k] = If[n == 0, 1, If[i < 1, 0, Sum[Function[t, b[t, Min[t, i - 1], k]][n - i j], {j, 1, n/i}] k + b[n, i - 1, k]]];
    A[n_, k_] := b[n, n, k];
    Table[A[n, d - n], {d, 0, 14}, {n, 0, d}] // Flatten (* Jean-François Alcover, Apr 30 2020, after Alois P. Heinz *)

Formula

G.f. of column k: Product_{j>=1} (1+(k-1)*x^j)/(1-x^j).
A(n,k) = Sum_{i=0..floor((sqrt(1+8*k)-1)/2)} k!/(k-i)! * A321878(n,i).

A321880 Number of partitions of n into colored blocks of equal parts with colors from a set of size n.

Original entry on oeis.org

1, 1, 4, 15, 44, 135, 456, 1239, 3424, 8694, 27240, 65846, 171864, 406133, 960848, 2615460, 5998416, 14304089, 32273100, 72271516, 153768520, 385905072, 817485768, 1841794483, 3915726528, 8388036950, 17125197336, 35051814558, 78986793592, 160176485813
Offset: 0

Views

Author

Alois P. Heinz, Aug 27 2019

Keywords

Examples

			a(3) = 15: 3a, 3b, 3c, 2a1a, 2a1b, 2a1c, 2b1a, 2b1b, 2b1c, 2c1a, 2c1b, 2c1c, 111a, 111b, 111c.
		

Crossrefs

Main diagonal of A321884.

Programs

  • Maple
    b:= proc(n, i, k) option remember; `if`(n=0, 1, `if`(i<1, 0, k*add(
          (t-> b(t, min(t, i-1), k))(n-i*j), j=1..n/i) +b(n, i-1, k)))
        end:
    a:= n-> b(n$3):
    seq(a(n), n=0..31);
  • Mathematica
    b[n_, i_, k_] := b[n, i, k] = If[n == 0, 1, If[i < 1, 0, Sum[Function[t, b[t, Min[t, i - 1], k]][n - i j], {j, 1, n/i}] k + b[n, i - 1, k]]];
    a[n_] := b[n, n, n];
    a /@ Range[0, 31] (* Jean-François Alcover, Dec 08 2020, after Alois P. Heinz *)

Formula

a(n) = [x^n] Product_{j=1..n} (1+(n-1)*x^j)/(1-x^j).
a(n) = A321884(n,n).
a(n) = Sum_{i=0..floor((sqrt(1+8*n)-1)/2)} n!/(n-i)! * A321878(n,i).
a(n) = n * A325916(n) for n > 0, a(n) = 1.

A305106 Number of unitary factorizations of Heinz numbers of integer partitions of n. Number of multiset partitions of integer partitions of n with pairwise disjoint blocks.

Original entry on oeis.org

1, 1, 2, 4, 7, 12, 21, 34, 55, 87, 138, 211, 324, 486, 727, 1079, 1584, 2305, 3337, 4789, 6830, 9712, 13689, 19225, 26841, 37322, 51598, 71108, 97580, 133350, 181558, 246335, 332991, 448706, 602607, 806732, 1077333, 1433885, 1903682, 2520246, 3328549, 4383929
Offset: 0

Views

Author

Gus Wiseman, May 25 2018

Keywords

Examples

			The a(6) = 21 unitary factorizations:
(13) (21) (22) (25) (27) (28) (30) (36) (40) (48) (64)
(2*11) (2*15) (3*7) (3*10) (3*16) (4*7) (4*9) (5*6) (5*8)
(2*3*5)
The a(6) = 21 multiset partitions:
{{6}}
{{2,4}}
{{1,5}}
{{3,3}}
{{2,2,2}}
{{1,1,4}}
{{1,2,3}}
{{1,1,2,2}}
{{1,1,1,3}}
{{1,1,1,1,2}}
{{1,1,1,1,1,1}}
{{1},{5}}
{{1},{2,3}}
{{2},{4}}
{{2},{1,3}}
{{2},{1,1,1,1}}
{{1,1},{4}}
{{1,1},{2,2}}
{{3},{1,2}}
{{3},{1,1,1}}
{{1},{2},{3}}
		

Crossrefs

Programs

  • Mathematica
    Table[Sum[BellB[Length[Union[y]]],{y,IntegerPartitions[n]}],{n,30}]
    (* Second program: *)
    b[n_, i_, k_] := b[n, i, k] = If[n == 0, 1, If[i < 1, 0, Sum[With[{t = n - i j}, b[t, Min[t, i - 1], k]], {j, 1, n/i}] k + b[n, i - 1, k]]];
    T[n_, k_] := Sum[b[n, n, k - i] (-1)^i Binomial[k, i], {i, 0, k}]/k!;
    a[n_] := Sum[T[n, k], {k, 0, Floor[(Sqrt[1 + 8n] - 1)/2]}];
    a /@ Range[0, 50] (* Jean-François Alcover, Dec 14 2020, after Alois P. Heinz in A321878 *)

A322304 Total number of colors in all partitions of n into colored blocks of equal parts, such that all colors from a given set are used and the colors are introduced in increasing order.

Original entry on oeis.org

0, 1, 2, 5, 9, 17, 32, 55, 93, 154, 257, 407, 648, 1003, 1546, 2367, 3566, 5323, 7889, 11579, 16854, 24495, 35171, 50345, 71520, 101184, 142118, 198981, 277260, 384457, 530875, 730220, 1000192, 1365105, 1856155, 2514737, 3398397, 4574460, 6141309, 8218229
Offset: 0

Views

Author

Alois P. Heinz, Aug 28 2019

Keywords

Examples

			a(4) = 9. The colored partitions are: 1111a, 2a11a, 22a, 3a1a, 4a, 2a11b, 3a1b.  The total number of colors used is 1+1+1+1+1+2+2 = 9.
		

Crossrefs

Programs

  • Maple
    b:= proc(n, i, k) option remember; `if`(n=0, 1, `if`(i<1, 0, add(
         (t-> b(t, min(t, i-1), k))(n-i*j), j=1..n/i)*k+b(n, i-1, k)))
        end:
    a:= proc(n) option remember; add(add(binomial(k, i)*(-1)^i*
          b(n$2, k-i), i=0..k)/(k-1)!, k=1..floor((sqrt(1+8*n)-1)/2))
        end:
    seq(a(n), n=0..44);
  • Mathematica
    b[n_, i_, k_] := b[n, i, k] = If[n == 0, 1, If[i < 1, 0, Sum[With[{t = n - i j}, b[t, Min[t, i - 1], k]], {j, 1, n/i}] k + b[n, i - 1, k]]];
    a[n_] := Sum[Sum[Binomial[k, i] (-1)^i b[n, n, k - i], {i, 0, k}]/(k - 1)!, {k, 1, Floor[(Sqrt[1 + 8n] - 1)/2]}];
    a /@ Range[0, 44] (* Jean-François Alcover, Dec 14 2020, after Alois P. Heinz *)

Formula

a(n) = Sum_{k=1..A003056(n)} k * A321878(n,k).

A327285 Number of partitions of n into colored blocks of equal parts, such that all colors from a set of size two are used and the colors are introduced in increasing order.

Original entry on oeis.org

1, 2, 5, 9, 17, 28, 47, 74, 116, 175, 263, 385, 560, 800, 1135, 1589, 2210, 3041, 4160, 5642, 7609, 10189, 13575, 17976, 23694, 31066, 40559, 52708, 68230, 87957, 112985, 144594, 184437, 234466, 297159, 375453, 473039, 594298, 744681, 930674, 1160271, 1442989
Offset: 3

Views

Author

Alois P. Heinz, Aug 28 2019

Keywords

Crossrefs

Column k=2 of A321878.

Programs

  • Maple
    b:= proc(n, i, k) option remember; `if`(n=0, 1, `if`(i<1, 0, add(
         (t-> b(t, min(t, i-1), k))(n-i*j), j=1..n/i)*k+b(n, i-1, k)))
        end:
    a:= n-> (k-> add(b(n$2, k-i)*(-1)^i*binomial(k, i), i=0..k)/k!)(2):
    seq(a(n), n=3..44);
  • Mathematica
    b[n_, i_, k_] := b[n, i, k] = If[n == 0, 1, If[i < 1, 0, Sum[With[{t = n - i j}, b[t, Min[t, i - 1], k]], {j, 1, n/i}] k + b[n, i - 1, k]]];
    a[n_] := With[{k = 2}, Sum[b[n, n, k-i] (-1)^i Binomial[k, i], {i, 0, k}]/ k!];
    a /@ Range[3, 44] (* Jean-François Alcover, Dec 14 2020, after Alois P. Heinz *)

Formula

a(n) ~ exp(Pi*sqrt(n)) / (16*n). - Vaclav Kotesovec, Sep 18 2019

A327286 Number of partitions of n into colored blocks of equal parts, such that all colors from a set of size three are used and the colors are introduced in increasing order.

Original entry on oeis.org

1, 2, 5, 10, 21, 37, 67, 112, 187, 302, 479, 741, 1136, 1707, 2539, 3732, 5424, 7804, 11133, 15743, 22088, 30774, 42582, 58540, 80007, 108725, 146955, 197646, 264525, 352433, 467541, 617651, 812734, 1065417, 1391592, 1811296, 2349775, 3038515, 3917052, 5034647
Offset: 6

Views

Author

Alois P. Heinz, Aug 28 2019

Keywords

Crossrefs

Column k=3 of A321878.

Programs

  • Maple
    b:= proc(n, i, k) option remember; `if`(n=0, 1, `if`(i<1, 0, add(
         (t-> b(t, min(t, i-1), k))(n-i*j), j=1..n/i)*k+b(n, i-1, k)))
        end:
    a:= n-> (k-> add(b(n$2, k-i)*(-1)^i*binomial(k, i), i=0..k)/k!)(3):
    seq(a(n), n=6..47);
  • Mathematica
    b[n_, i_, k_] := b[n, i, k] = If[n == 0, 1, If[i < 1, 0, Sum[With[{t = n - i j}, b[t, Min[t, i - 1], k]], {j, 1, n/i}] k + b[n, i - 1, k]]];
    a[n_] := With[{k = 3}, Sum[b[n, n, k-i] (-1)^i Binomial[k, i], {i, 0, k}]/ k!];
    a /@ Range[6, 47] (* Jean-François Alcover, Dec 14 2020, after Alois P. Heinz *)

Formula

a(n) ~ exp(sqrt(2*(Pi^2 - 6*polylog(2,-2))*n/3)) * sqrt(Pi^2 - 6*polylog(2,-2)) / (72*Pi*n). - Vaclav Kotesovec, Sep 18 2019

A327287 Number of partitions of n into colored blocks of equal parts, such that all colors from a set of size four are used and the colors are introduced in increasing order.

Original entry on oeis.org

1, 2, 5, 10, 20, 40, 72, 127, 217, 362, 587, 954, 1494, 2330, 3562, 5403, 8060, 11954, 17531, 25490, 36733, 52570, 74620, 105273, 147479, 205390, 284516, 391819, 536891, 732028, 993540, 1342174, 1805795, 2419115, 3228530, 4292484, 5686507, 7506642, 9877321
Offset: 10

Views

Author

Alois P. Heinz, Aug 28 2019

Keywords

Crossrefs

Column k=4 of A321878.

Programs

  • Maple
    b:= proc(n, i, k) option remember; `if`(n=0, 1, `if`(i<1, 0, add(
         (t-> b(t, min(t, i-1), k))(n-i*j), j=1..n/i)*k+b(n, i-1, k)))
        end:
    a:= n-> (k-> add(b(n$2, k-i)*(-1)^i*binomial(k, i), i=0..k)/k!)(4):
    seq(a(n), n=10..49);
  • Mathematica
    b[n_, i_, k_] := b[n, i, k] = If[n == 0, 1, If[i < 1, 0, Sum[With[{t = n - i j}, b[t, Min[t, i - 1], k]], {j, 1, n/i}] k + b[n, i - 1, k]]];
    a[n_] := With[{k = 4}, Sum[b[n, n, k-i] (-1)^i Binomial[k, i], {i, 0, k}]/ k!];
    a /@ Range[10, 49] (* Jean-François Alcover, Dec 14 2020, after Alois P. Heinz *)

Formula

a(n) ~ exp(sqrt(2*(Pi^2 - 6*polylog(2,-3))*n/3)) * sqrt(Pi^2 - 6*polylog(2,-3)) / (4*4!*sqrt(12)*Pi*n). - Vaclav Kotesovec, Sep 18 2019

A327288 Number of partitions of n into colored blocks of equal parts, such that all colors from a set of size five are used and the colors are introduced in increasing order.

Original entry on oeis.org

1, 2, 5, 10, 20, 36, 73, 125, 222, 372, 623, 1002, 1611, 2559, 3984, 6139, 9355, 14096, 21028, 31093, 45523, 66403, 95779, 137495, 195813, 277531, 390428, 546942, 761113, 1054749, 1454412, 1996271, 2727247, 3711683, 5029288, 6789347, 9130315, 12234596, 16335987
Offset: 15

Views

Author

Alois P. Heinz, Aug 28 2019

Keywords

Crossrefs

Column k=5 of A321878.

Programs

  • Maple
    b:= proc(n, i, k) option remember; `if`(n=0, 1, `if`(i<1, 0, add(
         (t-> b(t, min(t, i-1), k))(n-i*j), j=1..n/i)*k+b(n, i-1, k)))
        end:
    a:= n-> (k-> add(b(n$2, k-i)*(-1)^i*binomial(k, i), i=0..k)/k!)(5):
    seq(a(n), n=15..53);
  • Mathematica
    b[n_, i_, k_] := b[n, i, k] = If[n == 0, 1, If[i < 1, 0, Sum[With[{t = n - i j}, b[t, Min[t, i - 1], k]], {j, 1, n/i}] k + b[n, i - 1, k]]];
    a[n_] := With[{k = 5}, Sum[b[n, n, k-i] (-1)^i Binomial[k, i], {i, 0, k}]/ k!];
    a /@ Range[15, 53] (* Jean-François Alcover, Dec 14 2020, after Alois P. Heinz *)

Formula

a(n) ~ exp(sqrt(2*(Pi^2 - 6*polylog(2,-4))*n/3)) * sqrt(Pi^2 - 6*polylog(2,-4)) / (4*5!*sqrt(15)*Pi*n). - Vaclav Kotesovec, Sep 18 2019

A327289 Number of partitions of n into colored blocks of equal parts, such that all colors from a set of size six are used and the colors are introduced in increasing order.

Original entry on oeis.org

1, 2, 5, 10, 20, 36, 65, 123, 210, 362, 603, 994, 1595, 2541, 3956, 6225, 9501, 14516, 21820, 32703, 48315, 71175, 103589, 150167, 216413, 309627, 440400, 623404, 877303, 1228493, 1712235, 2374639, 3278894, 4507571, 6175713, 8421243, 11447049, 15496728
Offset: 21

Views

Author

Alois P. Heinz, Aug 28 2019

Keywords

Crossrefs

Column k=6 of A321878.

Programs

  • Maple
    b:= proc(n, i, k) option remember; `if`(n=0, 1, `if`(i<1, 0, add(
         (t-> b(t, min(t, i-1), k))(n-i*j), j=1..n/i)*k+b(n, i-1, k)))
        end:
    a:= n-> (k-> add(b(n$2, k-i)*(-1)^i*binomial(k, i), i=0..k)/k!)(6):
    seq(a(n), n=21..59);

Formula

a(n) ~ exp(sqrt(2*(Pi^2 - 6*polylog(2,-5))*n/3)) * sqrt(Pi^2 - 6*polylog(2,-5)) / (4*6!*sqrt(18)*Pi*n). - Vaclav Kotesovec, Sep 18 2019

A327290 Number of partitions of n into colored blocks of equal parts, such that all colors from a set of size seven are used and the colors are introduced in increasing order.

Original entry on oeis.org

1, 2, 5, 10, 20, 36, 65, 110, 204, 337, 573, 934, 1527, 2416, 3826, 5907, 9088, 13963, 21070, 31642, 47131, 69707, 102214, 149143, 215754, 310547, 443840, 633139, 895294, 1262971, 1770236, 2473601, 3436809, 4761393, 6561269, 9015761, 12330231, 16812326
Offset: 28

Views

Author

Alois P. Heinz, Aug 28 2019

Keywords

Crossrefs

Column k=7 of A321878.

Programs

  • Maple
    b:= proc(n, i, k) option remember; `if`(n=0, 1, `if`(i<1, 0, add(
         (t-> b(t, min(t, i-1), k))(n-i*j), j=1..n/i)*k+b(n, i-1, k)))
        end:
    a:= n-> (k-> add(b(n$2, k-i)*(-1)^i*binomial(k, i), i=0..k)/k!)(7):
    seq(a(n), n=28..65);

Formula

a(n) ~ exp(sqrt(2*(Pi^2 - 6*polylog(2,-6))*n/3)) * sqrt(Pi^2 - 6*polylog(2,-6)) / (4*7!*sqrt(21)*Pi*n). - Vaclav Kotesovec, Sep 18 2019
Showing 1-10 of 13 results. Next