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.

A339006 Sum over all partitions lambda of n of binomial(|lambda|, |{lambda}|).

Original entry on oeis.org

1, 1, 3, 5, 11, 20, 40, 72, 130, 227, 395, 671, 1124, 1864, 3040, 4909, 7830, 12394, 19388, 30145, 46395, 70977, 107661, 162383, 243108, 362037, 535684, 788677, 1154605, 1682402, 2439123, 3520706, 5058786, 7239027, 10315920, 14644309, 20709800, 29182353
Offset: 0

Views

Author

Alois P. Heinz, Nov 18 2020

Keywords

Comments

|lambda| is the number of parts in lambda and |{lambda}| is the number of distinct parts.

Crossrefs

Programs

  • Maple
    b:= proc(n, i, p, d) option remember; `if`(n=0, binomial(p, d),
         `if`(i<1, 0, add(b(n-i*j, i-1, p+j, `if`(j=0, d, d+1)), j=0..n/i)))
        end:
    a:= n-> b(n$2, 0$2):
    seq(a(n), n=0..50);
  • Mathematica
    b[n_, i_, p_, d_] := b[n, i, p, d] = If[n == 0, Binomial[p, d],
        If[i<1, 0, Sum[b[n-i*j, i-1, p+j, If[j == 0, d, d+1]], {j, 0, n/i}]]];
    a[n_] := b[n, n, 0, 0];
    Table[a[n], {n, 0, 50}] (* Jean-François Alcover, Aug 01 2021, after Alois P. Heinz *)

A339011 Sum over all partitions of n of the product of the number of parts and the number of distinct parts.

Original entry on oeis.org

0, 1, 3, 8, 17, 34, 61, 107, 176, 284, 442, 676, 1007, 1483, 2140, 3055, 4299, 5993, 8255, 11284, 15272, 20529, 27373, 36274, 47735, 62484, 81293, 105251, 135555, 173818, 221836, 282003, 356980, 450256, 565765, 708537, 884296, 1100287, 1364736, 1687952, 2081724
Offset: 0

Views

Author

Alois P. Heinz, Nov 18 2020

Keywords

Crossrefs

Essentially partial sums of A093694.

Programs

  • Maple
    b:= proc(n, i, p, d) option remember; `if`(n=0, d*p, `if`(i<1, 0,
          add(b(n-i*j, i-1, p+j, `if`(j=0, d, d+1)), j=0..n/i)))
        end:
    a:= n-> b(n$2, 0$2):
    seq(a(n), n=0..50);
    # second Maple program:
    b:= proc(n, i) option remember; `if`(n<=0 or i=0, [0$2],
         `if`(i=1, [1, n], b(n, i-1)+ (p-> p+[0, p[1]])(b(n-i, i))))
        end:
    a:= proc(n) option remember; b(n$2)[2]+`if`(n<0, 0, a(n-1)) end:
    seq(a(n), n=0..100);  # Alois P. Heinz, Jul 25 2022
  • Mathematica
    b[n_, i_, p_, d_] := b[n, i, p, d] = If[n == 0, d*p, If[i < 1, 0,
         Sum[b[n - i*j, i - 1, p + j, If[j == 0, d, d + 1]], {j, 0, n/i}]]];
    a[n_] := b[n, n, 0, 0];
    a /@ Range[0, 50] (* Jean-François Alcover, Mar 09 2021, after Alois P. Heinz *)

A339394 Sum over all partitions of n of the LCM of the number of parts and the number of distinct parts.

Original entry on oeis.org

0, 1, 3, 6, 15, 26, 43, 81, 138, 218, 320, 514, 751, 1131, 1570, 2319, 3159, 4457, 6077, 8344, 11224, 15337, 20297, 26908, 35773, 46434, 60711, 78433, 100987, 129222, 166590, 209719, 267120, 335842, 423341, 527739, 659974, 816805, 1015990, 1251686, 1543864
Offset: 0

Views

Author

Alois P. Heinz, Dec 02 2020

Keywords

Crossrefs

Programs

  • Maple
    b:= proc(n, i, p, d) option remember; `if`(n=0, ilcm(p, d),
          add(b(n-i*j, i-1, p+j, d+signum(j)), j=`if`(i>1, 0..n/i, n)))
        end:
    a:= n-> b(n$2, 0$2):
    seq(a(n), n=0..50);
  • Mathematica
    b[n_, i_, p_, d_] := b[n, i, p, d] = If[n == 0, LCM[p, d],
         Sum[b[n - i*j, i - 1, p + j, d + Sign[j]],
         {j, If[i > 1, Range[0, n/i], {n}]}]];
    a[n_] := b[n, n, 0, 0];
    a /@ Range[0, 50] (* Jean-François Alcover, Mar 09 2021, after Alois P. Heinz *)
Showing 1-3 of 3 results.