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 1-4 of 4 results.

A188216 Expansion of 1 + Sum_{n>=1} (x^(n^2) / Product_{k>=n} (1 - x^k)).

Original entry on oeis.org

1, 1, 1, 2, 4, 5, 8, 12, 17, 25, 34, 46, 64, 86, 114, 151, 200, 258, 335, 431, 552, 703, 891, 1121, 1411, 1764, 2196, 2725, 3374, 4155, 5111, 6260, 7650, 9319, 11329, 13726, 16608, 20031, 24114, 28962, 34725, 41529, 49595, 59095, 70304, 83476, 98968, 117109
Offset: 0

Views

Author

Joerg Arndt, Mar 24 2011

Keywords

Comments

Number of partitions of n such that if k is the least part, then k occurs at least k times. - Joerg Arndt, Apr 17 2011

Crossrefs

Cf. A096403 (expansion of sum(n>=1, x^(n^2) / prod(k>=n+1, 1-x^k)) ).
Cf. A003114 (largest part k occurs at least k times).

Programs

  • Maple
    b:= proc(n, i) option remember; `if`(n=0, 1,
         `if`(i>n, 0, b(n, i+1)+b(n-i, i)))
        end:
    a:= n-> `if`(n=0, 1, add(b(n-j^2, j), j=1..isqrt(n))):
    seq(a(n), n=0..50);  # Alois P. Heinz, Jan 03 2021
  • Mathematica
    b[n_, i_] := b[n, i] = If[n==0, 1, If[i>n, 0, b[n, i+1] + b[n-i, i]]];
    a[n_] := If[n==0, 1, Sum[b[n - j^2, j], {j, 1, Sqrt[n]}]];
    a /@ Range[0, 50] (* Jean-François Alcover, Jan 25 2021, after Alois P. Heinz *)
  • PARI
    N=55; x='x+O('x^N);
    t=1+sum(n=1,N,x^(n^2)/prod(k=n,N,1-x^k));
    Vec(t)

A240175 Number of partitions of n such that the least part is less than its multiplicity.

Original entry on oeis.org

0, 0, 1, 1, 2, 3, 6, 7, 12, 16, 24, 32, 47, 60, 84, 110, 148, 191, 254, 323, 423, 535, 687, 864, 1100, 1371, 1726, 2141, 2669, 3290, 4075, 4990, 6136, 7481, 9137, 11087, 13471, 16264, 19659, 23641, 28438, 34060, 40801, 48676, 58074, 69049, 82064, 97246
Offset: 0

Views

Author

Clark Kimberling, Apr 02 2014

Keywords

Examples

			a(8) counts these 12 partitions:  611, 5111, 4211, 41111, 3311, 32111, 311111, 2222, 22211, 221111, 2111111, 11111111.
		

Crossrefs

Programs

  • Mathematica
    z = 60; f[n_] := f[n] = IntegerPartitions[n];
    Table[Count[f[n], p_ /; Min[p] < Count[p, Min[p]]], {n, 0, z}](* A240175 *)
    Table[Count[f[n], p_ /; Min[p] <= Count[p, Min[p]]], {n, 0, z}](* A188216 *)
    Table[Count[f[n], p_ /; Min[p] == Count[p, Min[p]]], {n, 0, z}](* A096403 *)
    Table[Count[f[n], p_ /; Min[p] > Count[p, Min[p]]], {n, 0, z}] (* A240176 *)
    Table[Count[f[n], p_ /; Min[p] >= Count[p, Min[p]]], {n, 0, z}] (* A240177 *)

Formula

a(n) = A188216(n) - A096403(n), for n >= 0.

A240176 Number of partitions of n such that (least part) > (multiplicity of least part).

Original entry on oeis.org

1, 0, 1, 1, 1, 2, 3, 3, 5, 5, 8, 10, 13, 15, 21, 25, 31, 39, 50, 59, 75, 89, 111, 134, 164, 194, 240, 285, 344, 410, 493, 582, 699, 824, 981, 1157, 1369, 1606, 1901, 2223, 2613, 3054, 3579, 4166, 4871, 5658, 6590, 7645, 8877, 10264, 11900, 13733, 15868
Offset: 0

Views

Author

Clark Kimberling, Apr 02 2014

Keywords

Examples

			a(8) counts these 5 partitions:  8, 61, 53, 44, 332.
		

Crossrefs

Programs

  • Mathematica
    z = 60; f[n_] := f[n] = IntegerPartitions[n]; t1 = Table[Count[f[n], p_ /; Min[p] < Count[p, Min[p]]], {n, 0, z}]  (* A240175 *)
    t2 = Table[Count[f[n], p_ /; Min[p] <= Count[p, Min[p]]], {n, 0, z}] (* A188216 *)
    t3 = Table[Count[f[n], p_ /; Min[p] == Count[p, Min[p]]], {n, 0, z}] (* A096403 *)
    t4 = Table[Count[f[n], p_ /; Min[p] > Count[p, Min[p]]], {n, 0, z}] (* A240176 *)
    t5 = Table[Count[f[n], p_ /; Min[p] >= Count[p, Min[p]]], {n, 0, z}] (* A240177 *)

Formula

a(n) + A240175(n) + A096403(n) = A000041(n), for n >= 0.

A240177 Number of partitions of n such that (least part) >= (multiplicity of least part).

Original entry on oeis.org

1, 1, 1, 2, 3, 4, 5, 8, 10, 14, 18, 24, 30, 41, 51, 66, 83, 106, 131, 167, 204, 257, 315, 391, 475, 587, 710, 869, 1049, 1275, 1529, 1852, 2213, 2662, 3173, 3796, 4506, 5373, 6356, 7544, 8900, 10523, 12373, 14585, 17101, 20085, 23494, 27508, 32087, 37471
Offset: 0

Views

Author

Clark Kimberling, Apr 02 2014

Keywords

Examples

			a(6) counts these 5 partitions:  6, 51, 42, 33, 321.
		

Crossrefs

Programs

  • Mathematica
    z = 60; f[n_] := f[n] = IntegerPartitions[n]; t1 = Table[Count[f[n], p_ /; Min[p] < Count[p, Min[p]]], {n, 0, z}]  (* A240175 *)
    t2 = Table[Count[f[n], p_ /; Min[p] <= Count[p, Min[p]]], {n, 0, z}] (* A188216 *)
    t3 = Table[Count[f[n], p_ /; Min[p] == Count[p, Min[p]]], {n, 0, z}] (* A096403 *)
    t4 = Table[Count[f[n], p_ /; Min[p] > Count[p, Min[p]]], {n, 0, z}] (* A240176 *)
    t5 = Table[Count[f[n], p_ /; Min[p] >= Count[p, Min[p]]], {n, 0, z}] (* A240177 *)

Formula

a(n) = A096403(n) + A240176(n), for n >= 0.
Showing 1-4 of 4 results.