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 1-3 of 3 results.

A237800 Number of partitions of n such that 2*(least part) >= number of parts.

Original entry on oeis.org

1, 2, 2, 3, 3, 5, 5, 8, 9, 12, 14, 19, 21, 27, 32, 39, 45, 56, 64, 78, 90, 107, 124, 148, 169, 199, 229, 268, 306, 357, 406, 471, 536, 617, 701, 805, 910, 1041, 1177, 1341, 1511, 1717, 1931, 2187, 2457, 2773, 3109, 3503, 3918, 4403, 4919, 5514, 6150, 6881
Offset: 1

Views

Author

Clark Kimberling, Feb 15 2014

Keywords

Examples

			a(7) = 5 counts these partitions: 7, 61, 52, 43, 322.
		

Crossrefs

Programs

  • Mathematica
    z = 55; q[n_] := q[n] = IntegerPartitions[n]; t[p_] := Length[p];
    Table[Count[q[n], p_ /; 2 Min[p] < t[p]], {n, z}]   (* A237758 *)
    Table[Count[q[n], p_ /; 2 Min[p] == t[p]], {n, z}]  (* A237757 *)
    Table[Count[q[n], p_ /; 2 Min[p] > t[p]], {n, z}]   (* A237799 *)
    Table[Count[q[n], p_ /; 2 Min[p] >= t[p]], {n, z}]  (* A237800 *)

A118084 Number of partitions of n such that largest part k occurs at most floor(k/2) times.

Original entry on oeis.org

0, 1, 2, 3, 5, 7, 11, 16, 23, 33, 46, 63, 86, 116, 153, 203, 265, 345, 444, 571, 727, 925, 1166, 1468, 1836, 2293, 2845, 3525, 4345, 5347, 6550, 8011, 9758, 11867, 14380, 17399, 20984, 25269, 30341, 36376, 43500, 51943, 61877, 73608, 87373, 103571
Offset: 1

Views

Author

Emeric Deutsch, Apr 12 2006

Keywords

Comments

Also number of partitions of n such that if the number of parts is k, then the smallest part is at most floor(k/2). Example: a(8)=16 because we have [7,1],[6,1,1],[5,2,1],[4,3,1],[5,1,1,1],[4,2,1,1],[3,3,1,1],[3,2,2,1],[2,2,2,2],[4,1,1,1,1],[3,2,1,1,1],[2,2,2,1,1],[3,1,1,1,1,1],[2,2,1,1,1,1],[2,1,1,1,1,1,1] and [1,1,1,1,1,1,1,1].

Examples

			a(8)=16 because we have [8],[7,1],[6,2],[6,1,1],[5,3],[5,2,1],[5,1,1,1],[4,4],[4,3,1],[4,2,2],[4,2,1,1],[4,1,1,1,1],[3,2,2,1],[3,2,1,1,1],[3,1,1,1,1,1] and [2,1,1,1,1,1,1].
		

Crossrefs

Programs

  • Maple
    g:=sum(x^k*(1-x^(k*(floor(k/2))))/product(1-x^j,j=1..k),k=1..85): gser:=series(g,x=0,55): seq(coeff(gser,x,n),n=1..50);
  • Mathematica
    z=55 ; q[n_] := q[n] = IntegerPartitions[n]; t[p_] := Length[p];
    Table[Count[q[n], p_ /; 2 Min[p] <= t[p]], {n,z}] (* Clark Kimberling, Feb 15 2014 *)

Formula

G.f.=sum(x^k*(1-x^(k(floor(k/2))))/product(1-x^j, j=1..k), k=1..infinity).

A237758 Number of partitions of n such that 2*(least part) < number of parts.

Original entry on oeis.org

0, 0, 1, 2, 4, 6, 10, 14, 21, 30, 42, 58, 80, 108, 144, 192, 252, 329, 426, 549, 702, 895, 1131, 1427, 1789, 2237, 2781, 3450, 4259, 5247, 6436, 7878, 9607, 11693, 14182, 17172, 20727, 24974, 30008, 35997, 43072, 51457, 61330, 72988, 86677, 102785, 121645
Offset: 1

Views

Author

Clark Kimberling, Feb 15 2014

Keywords

Examples

			a(5) = 4 counts these partitions: 311, 221, 2111, 11111.
		

Crossrefs

Programs

  • Mathematica
    z = 55; q[n_] := q[n] = IntegerPartitions[n]; t[p_] := Length[p];
    Table[Count[q[n], p_ /; 2 Min[p] < t[p]], {n, z}]   (* A237758 *)
    Table[Count[q[n], p_ /; 2 Min[p] <= t[p]], {n, z}]  (* A118084 *)
    Table[Count[q[n], p_ /; 2 Min[p] == t[p]], {n, z}]  (* A237757 *)
    Table[Count[q[n], p_ /; 2 Min[p] > t[p]], {n, z}]   (* A237799 *)
    Table[Count[q[n], p_ /; 2 Min[p] >= t[p]], {n, z}]  (* A237800 *)
Showing 1-3 of 3 results.