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.

Previous Showing 11-17 of 17 results.

A322878 Number of set partitions of [n] such that the maximal absolute difference between the least elements of consecutive blocks equals five.

Original entry on oeis.org

0, 1, 19, 171, 1293, 9320, 66992, 488526, 3637440, 27735903, 216992278, 1743777862, 14401360577, 122242150172, 1066284279026, 9554869690126, 87923414758506, 830459368379431, 8047463255217118, 79967170844047637, 814439368083686232, 8497321384591725159
Offset: 5

Views

Author

Alois P. Heinz, Dec 29 2018

Keywords

Crossrefs

Column k=5 of A287215.

Programs

  • Maple
    b:= proc(n, k, m, l) option remember; `if`(n<1, 1,
         `if`(l-n>k, 0, b(n-1, k, m+1, n))+m*b(n-1, k, m, l))
        end:
    A:= (n, k)-> b(n-1, min(k, n-1), 1, n):
    a:= n-> (k-> A(n, k)-A(n, k-1))(5):
    seq(a(n), n=5..30);
  • Mathematica
    b[n_, k_, m_, l_] := b[n, k, m, l] = If[n < 1, 1, If[l - n > k, 0, b[n - 1, k, m + 1, n]] + m b[n - 1, k, m, l]];
    A[n_, k_] := b[n - 1, Min[k, n - 1], 1, n];
    a[n_] := With[{k = 5}, A[n, k] - A[n, k - 1]];
    a /@ Range[5, 30] (* Jean-François Alcover, May 05 2020, after Maple *)

Formula

a(n) = A287255(n) - A287254(n).

A322879 Number of set partitions of [n] such that the maximal absolute difference between the least elements of consecutive blocks equals six.

Original entry on oeis.org

0, 1, 35, 413, 3709, 30396, 242366, 1934021, 15653524, 129267234, 1091892025, 9444993005, 83722879838, 760771479660, 7087056828919, 67674638461955, 662248199987728, 6638947646238102, 68153572265860585, 716151632403862252, 7699437833837232406
Offset: 6

Views

Author

Alois P. Heinz, Dec 29 2018

Keywords

Crossrefs

Column k=6 of A287215.

Programs

  • Maple
    b:= proc(n, k, m, l) option remember; `if`(n<1, 1,
         `if`(l-n>k, 0, b(n-1, k, m+1, n))+m*b(n-1, k, m, l))
        end:
    A:= (n, k)-> b(n-1, min(k, n-1), 1, n):
    a:= n-> (k-> A(n, k)-A(n, k-1))(6):
    seq(a(n), n=6..30);

Formula

a(n) = A287256(n) - A287255(n).

A322880 Number of set partitions of [n] such that the maximal absolute difference between the least elements of consecutive blocks equals seven.

Original entry on oeis.org

0, 1, 67, 1059, 11373, 106256, 940608, 8193031, 71568443, 633413486, 5710573774, 52579554510, 494986212033, 4766754646529, 46966622143740, 473477764449909, 4883216510830794, 51513192445470426, 555667122424414886, 6127026713823497897, 69034256792655555566
Offset: 7

Views

Author

Alois P. Heinz, Dec 29 2018

Keywords

Crossrefs

Column k=7 of A287215.

Programs

  • Maple
    b:= proc(n, k, m, l) option remember; `if`(n<1, 1,
         `if`(l-n>k, 0, b(n-1, k, m+1, n))+m*b(n-1, k, m, l))
        end:
    A:= (n, k)-> b(n-1, min(k, n-1), 1, n):
    a:= n-> (k-> A(n, k)-A(n, k-1))(7):
    seq(a(n), n=7..30);

Formula

a(n) = A287257(n) - A287256(n).

A322881 Number of set partitions of [n] such that the maximal absolute difference between the least elements of consecutive blocks equals eight.

Original entry on oeis.org

0, 1, 131, 2837, 36733, 392532, 3862958, 36745885, 346270455, 3276723147, 31384368348, 305668217577, 3035028866706, 30761374688048, 318435571825333, 3367380704425616, 36376061350280633, 401367264163810215, 4522617803400779891, 52030240381937090624
Offset: 8

Views

Author

Alois P. Heinz, Dec 29 2018

Keywords

Crossrefs

Column k=8 of A287215.

Programs

  • Maple
    b:= proc(n, k, m, l) option remember; `if`(n<1, 1,
         `if`(l-n>k, 0, b(n-1, k, m+1, n))+m*b(n-1, k, m, l))
        end:
    A:= (n, k)-> b(n-1, min(k, n-1), 1, n):
    a:= n-> (k-> A(n, k)-A(n, k-1))(8):
    seq(a(n), n=8..30);

Formula

a(n) = A287258(n) - A287257(n).

A322882 Number of set partitions of [n] such that the maximal absolute difference between the least elements of consecutive blocks equals nine.

Original entry on oeis.org

0, 1, 259, 7851, 123693, 1517480, 16628928, 172861375, 1757583339, 17780116911, 180778826049, 1858914009077, 19407229306905, 206203531592425, 2232778235440364, 24655217395787251, 277719538910592762, 3191229583066629810, 37404691679158439649
Offset: 9

Views

Author

Alois P. Heinz, Dec 29 2018

Keywords

Crossrefs

Column k=9 of A287215.

Programs

  • Maple
    b:= proc(n, k, m, l) option remember; `if`(n<1, 1,
         `if`(l-n>k, 0, b(n-1, k, m+1, n))+m*b(n-1, k, m, l))
        end:
    A:= (n, k)-> b(n-1, min(k, n-1), 1, n):
    a:= n-> (k-> A(n, k)-A(n, k-1))(9):
    seq(a(n), n=9..30);

Formula

a(n) = A287259(n) - A287258(n).

A322883 Number of set partitions of [n] such that the maximal absolute difference between the least elements of consecutive blocks equals ten.

Original entry on oeis.org

0, 1, 515, 22253, 430909, 6094476, 74507486, 847129333, 9296465127, 100540964675, 1085004090887, 11775039127122, 129155075413877, 1436488582202316, 16235344928131625, 186710546094489052, 2186538096666720967, 26085011069325363939, 317049671003606985326
Offset: 10

Views

Author

Alois P. Heinz, Dec 29 2018

Keywords

Crossrefs

Column k=10 of A287215.

Programs

  • Maple
    b:= proc(n, k, m, l) option remember; `if`(n<1, 1,
         `if`(l-n>k, 0, b(n-1, k, m+1, n))+m*b(n-1, k, m, l))
        end:
    A:= (n, k)-> b(n-1, min(k, n-1), 1, n):
    a:= n-> (k-> A(n, k)-A(n, k-1))(10):
    seq(a(n), n=10..30);

Formula

a(n) = A287260(n) - A287259(n).

A322884 Number of set partitions of [2n] such that the maximal absolute difference between the least elements of consecutive blocks equals n.

Original entry on oeis.org

1, 1, 5, 39, 493, 9320, 242366, 8193031, 346270455, 17780116911, 1085004090887, 77324278953174, 6344818280326312, 592415284729545433, 62319734032202722887, 7323734663214254662683, 954467851066831095051393, 137065739258353347820981920
Offset: 0

Views

Author

Alois P. Heinz, Dec 29 2018

Keywords

Comments

a(0) = 1 by convention.

Examples

			a(1) = 1: 1|2.
a(2) = 5: 124|3, 12|34, 12|3|4, 13|2|4, 1|23|4.
		

Crossrefs

Cf. A287215.

Programs

  • Maple
    b:= proc(n, k, m, l) option remember; `if`(n<1, 1,
         `if`(l-n>k, 0, b(n-1, k, m+1, n))+m*b(n-1, k, m, l))
        end:
    A:= (n, k)-> b(n-1, min(k, n-1), 1, n):
    a:= n-> A(2*n, n)-`if`(n=0, 0, A(2*n, n-1)):
    seq(a(n), n=0..20);
  • Mathematica
    b[n_, k_, m_, l_] := b[n, k, m, l] = If[n < 1, 1, If[l - n > k, 0, b[n - 1, k, m + 1, n]] + m b[n - 1, k, m, l]];
    A[n_, k_] := b[n - 1, Min[k, n - 1], 1, n];
    a[n_] := A[2 n, n] - If[n == 0, 0, A[2 n, n - 1]];
    Table[a[n], {n, 0, 20}] (* Jean-François Alcover, Jan 03 2019, translated from Maple *)

Formula

a(n) = A287215(2n,n).
Previous Showing 11-17 of 17 results.