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 1-5 of 5 results.

A236002 Number of overcompositions of n.

Original entry on oeis.org

1, 2, 4, 12, 26, 60, 144, 324, 728, 1602, 3576, 7808, 17068, 36908, 79520, 170704, 364794, 777036, 1649456, 3491188, 7367544, 15513336, 32584648, 68307264, 142904080, 298448914, 622235060, 1295320004, 2692583916, 5589586996, 11588905844, 23999052692
Offset: 0

Views

Author

Omar E. Pol, Jan 19 2014

Keywords

Comments

Analog to overpartitions, here an overcomposition is defined to be a composition in which the first occurrence of each distinct number may be overlined (see example).
Also 1 together with the row sums of A235999.
For the number of partitions of n see A000041.
For the number of compositions of n see A011782.
For the number of overpartitions of n see A015128.
Note that there are several orderings of overcompositions, the same as the orderings of compositions, but apparently for every ordering of overcompositions there are also several suborderings according to the arrangements of the overlined parts. The same for overpartitions. See one of them in Example section.

Examples

			For n = 4 the 26 overcompositions of 4 are: [4], [4'], [1,3], [1',3], [1,3'], [1',3'], [2,2], [2',2], [1,1,2], [1',1,2], [1,1,2'], [1',1,2'], [3,1], [3',1], [3,1'], [3',1'], [1,2,1], [1',2,1], [1,2',1], [1',2',1], [2,1,1], [2',1,1], [2,1',1], [2',1',1], [1,1,1,1], [1',1,1,1].
		

Crossrefs

Formula

a(n) = Sum_{k=1..A003056(n)} 2^k*A235998(n,k), n >= 1.

Extensions

a(7) corrected and more terms added, Joerg Arndt, Jan 20 2014
a(19)-a(31) from Alois P. Heinz, Jan 20 2014

A235790 Triangle read by rows: T(n,k) = 2^k*A116608(n,k), n>=1, k>=1.

Original entry on oeis.org

2, 4, 4, 4, 6, 8, 4, 20, 8, 24, 8, 4, 44, 16, 8, 52, 40, 6, 68, 80, 8, 88, 120, 16, 4, 108, 200, 32, 12, 116, 296, 80, 4, 148, 416, 160, 8, 176, 536, 320, 8, 176, 776, 480, 32, 10, 220, 936, 832, 64, 4, 236, 1232, 1232, 160, 12, 272, 1472, 1872, 320
Offset: 1

Views

Author

Omar E. Pol, Jan 18 2014

Keywords

Comments

It appears that T(n,k) is the number of overpartitions of n having k distinct parts. (This is true by definition, Joerg Arndt, Jan 20 2014).
Row n has length A003056(n) hence the first element of column k is in row A000217(k).
The first element of column k is A000079(k).

Examples

			Triangle begins:
2;
4;
4,    4;
6,    8;
4,   20;
8,   24,    8;
4,   44,   16;
8,   52,   40;
6,   68,   80;
8,   88,  120,   16;
4,  108,  200,   32;
12, 116,  296,   80;
4,  148,  416,  160;
8,  176,  536,  320;
8,  176,  776,  480,   32;
10, 220,  936,  832,   64;
4,  236, 1232, 1232,  160;
12, 272, 1472, 1872,  320;
4,  284, 1880, 2592,  640;
12, 324, 2216, 3632, 1152;
8,  328, 2704, 4944, 1856, 64;
...
		

Crossrefs

Programs

  • Maple
    b:= proc(n, i) option remember; `if`(n=0, 1, `if`(i<1, 0,
          expand(b(n, i-1)+add(x*b(n-i*j, i-1), j=1..n/i))))
        end:
    T:= n->(p->seq(2^i*coeff(p, x, i), i=1..degree(p)))(b(n$2)):
    seq(T(n), n=1..20);  # Alois P. Heinz, Jan 20 2014
  • Mathematica
    b[n_, i_] := b[n, i] = If[n == 0, 1, If[i<1, 0, Expand[b[n, i-1] + Sum[x*b[n-i*j, i-1], {j, 1, n/i}]]]]; T[n_] := Function[p, Table[2^i * Coefficient[p, x, i], {i, 1, Exponent[p, x]}]][b[n, n]]; Table[T[n], {n, 1, 20}] // Flatten (* Jean-François Alcover, Oct 20 2016, after Alois P. Heinz *)

A235998 Triangle read by rows: T(n,k) is the number of compositions of n having k distinct parts (n>=1, 1<=k<=floor((sqrt(1+8*n)-1)/2)).

Original entry on oeis.org

1, 2, 2, 2, 3, 5, 2, 14, 4, 22, 6, 2, 44, 18, 4, 68, 56, 3, 107, 146, 4, 172, 312, 24, 2, 261, 677, 84, 6, 396, 1358, 288, 2, 606, 2666, 822, 4, 950, 5012, 2226, 4, 1414, 9542, 5304, 120, 5, 2238, 17531, 12514, 480, 2, 3418, 32412, 27904, 1800, 6, 5411, 58995, 61080, 5580
Offset: 1

Views

Author

Omar E. Pol, Jan 19 2014

Keywords

Comments

Row n has length A003056(n) hence the first element of column k is in row A000217(k).
The equivalent sequence for partitions is A116608.
For the number of compositions of n see A011782.
For the connection to overcompositions see A235999.
Row sums give A011782(n), n >= 1.
First column is A000005, second column is A131661.
T(k*(k+1)/2,k) = T(A000217(k),k) = A000142(k) = k!. - Alois P. Heinz, Jan 20 2014

Examples

			Triangle begins:
  1;
  2;
  2,    2;
  3,    5;
  2,   14;
  4,   22,     6;
  2,   44,    18;
  4,   68,    56;
  3,  107,   146;
  4,  172,   312,    24;
  2,  261,   677,    84;
  6,  396,  1358,   288;
  2,  606,  2666,   822;
  4,  950,  5012,  2226;
  4, 1414,  9542,  5304,  120;
  5, 2238, 17531, 12514,  480;
  2, 3418, 32412, 27904, 1800;
  6, 5411, 58995, 61080, 5580;
  ...
		

Crossrefs

Programs

  • Maple
    b:= proc(n, i, p) option remember; `if`(n=0, p!, `if`(i<1, 0,
          expand(add(b(n-i*j, i-1, p+j)/j!*`if`(j=0, 1, x), j=0..n/i))))
        end:
    T:= n-> (p-> seq(coeff(p, x, i), i=1..degree(p)))(b(n$2, 0)):
    seq(T(n), n=1..25); # Alois P. Heinz, Jan 20 2014, revised May 25 2014
  • Mathematica
    b[n_, i_, p_] := b[n, i, p] = If[n==0, p!, If[i<1, 0, Sum[b[n-i*j, i-1, p+ j]/j!*If[j==0, 1, x], {j, 0, n/i}]]]; T[n_] := Function[p, Table[ Coefficient[p, x, i], {i, 1, Exponent[p, x]}]][b[n, n, 0]]; Table[T[n], {n, 1, 25}] // Flatten (* Jean-François Alcover, Dec 10 2015, after Alois P. Heinz *)

Extensions

More terms from Alois P. Heinz, Jan 19 2014

A236625 Total number of parts in all overcompositions of n.

Original entry on oeis.org

0, 2, 6, 24, 66, 180, 496, 1272, 3202, 7798, 18980, 45076, 106288, 246956, 568776, 1299184, 2944654, 6630660, 14838606, 33026000, 73126376, 161198136, 353812612, 773645124, 1685548792, 3660364490, 7924414752, 17107225340, 36832846344, 79107019964, 169505684844
Offset: 0

Views

Author

Omar E. Pol, Feb 01 2014

Keywords

Comments

For the definition of overcomposition see A236002.
The equivalent sequence for overpartitions is A235792.
Row sums of triangle A236628.

Examples

			For n = 3 the 12 overcompositions of 3 are [3], [3'], [1, 2], [1', 2], [1, 2'], [1', 2'], [2, 1], [2', 1], [2, 1'], [2', 1'], [1, 1, 1], [1', 1, 1]. There are 24 parts, so a(3) = 24.
		

Crossrefs

Programs

  • Maple
    b:= proc(n, i, p) option remember; `if`(n=0, [p!, 0],
          `if`(i<1, 0, add((p-> p+[0, p[1]*j])(1/j!*
          `if`(j>0, 2, 1)*b(n-i*j, i-1, p+j)), j=0..n/i)))
        end:
    a:= n-> b(n$2, 0)[2]:
    seq(a(n), n=0..35);  # Alois P. Heinz, Apr 28 2016
  • Mathematica
    b[n_, i_, p_] := b[n, i, p] = If[n == 0, {p!, 0}, If[i < 1, {0, 0}, Sum[# + {0, #[[1]]*j}&[1/j!*If[j > 0, 2, 1]*b[n - i*j, i - 1, p + j]], {j, 0, n/i}]]];
    a[n_] := b[n, n, 0][[2]];
    Table[a[n], {n, 0, 35}] (* Jean-François Alcover, Nov 03 2022, after Alois P. Heinz *)

Extensions

a(6)-a(30) from Alois P. Heinz, Feb 02 2014

A236626 Sum of all parts of all overcompositions of n.

Original entry on oeis.org

2, 8, 36, 104, 300, 864, 2268, 5824, 14418, 35760, 85888, 204816, 479804, 1113280, 2560560, 5836704, 13209612, 29690208, 66332572, 147350880, 325780056, 716862256, 1571067072, 3429697920, 7461222850, 16178111560, 34973640108, 75392349648
Offset: 1

Views

Author

Omar E. Pol, Feb 01 2014

Keywords

Comments

For the definition of overcomposition see A236002.
The equivalent sequence for overpartitions is A235793.

Examples

			For n = 3 the 12 overcompositions of 3 are [3], [3'], [1, 2], [1', 2], [1, 2'], [1', 2'], [2, 1], [2', 1], [2, 1'], [2', 1'], [1, 1, 1], [1', 1, 1], hence the sum of all parts is 3+3+1+2+1+2+1+2+1+2+2+1+2+1+2+1+2+1+1+1+1+1+1+1 = 3*12 = 36, so a(3) = 36.
		

Crossrefs

Formula

a(n) = n*A236002(n).
Showing 1-5 of 5 results.