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 1-10 of 13 results. Next

A292549 Number of multisets of exactly n nonempty binary words with a total of 2n letters such that no word has a majority of 0's.

Original entry on oeis.org

1, 3, 10, 33, 98, 291, 826, 2320, 6342, 17188, 45750, 120733, 314690, 813854, 2085363, 5306878, 13406382, 33665476, 84031608, 208655086, 515469203, 1267600993, 3103490884, 7567559622, 18381579206, 44487740012, 107301636460, 257967350824, 618279370985
Offset: 0

Views

Author

Alois P. Heinz, Sep 18 2017

Keywords

Examples

			a(0) = 1: {}.
a(1) = 3: {01}, {10}, {11}.
a(2) = 10: {1,011}, {1,101}, {1,110}, {1,111}, {01,01}, {01,10}, {01,11}, {10,10}, {10,11}, {11,11}.
		

Crossrefs

Cf. A292506.

Programs

  • Maple
    g:= n-> 2^(n-1)+`if`(n::odd, 0, binomial(n, n/2)/2):
    a:= proc(n) option remember; `if`(n=0, 1, add(add(d*
          g(d+1), d=numtheory[divisors](j))*a(n-j), j=1..n)/n)
        end:
    seq(a(n), n=0..35);
  • Mathematica
    g[n_] := 2^(n-1) + If[OddQ[n], 0, Binomial[n, n/2]/2];
    a[n_] := a[n] = If[n == 0, 1, Sum[Sum[d*g[d+1], {d, Divisors[j]}]*a[n-j], {j, 1, n}]/n];
    Table[a[n], {n, 0, 35}] (* Jean-François Alcover, May 11 2019, after Alois P. Heinz *)

Formula

a(n) = A292506(2n,n) = A292506(2n+j,n+j) for j >= 0.
G.f.: Product_{j>=1} 1/(1-x^j)^A027306(j+1).
Euler transform of j-> A027306(j+1).

A209406 Triangular array read by rows: T(n,k) is the number of multisets of exactly k nonempty binary words with a total of n letters.

Original entry on oeis.org

2, 4, 3, 8, 8, 4, 16, 26, 12, 5, 32, 64, 44, 16, 6, 64, 164, 132, 62, 20, 7, 128, 384, 376, 200, 80, 24, 8, 256, 904, 1008, 623, 268, 98, 28, 9, 512, 2048, 2632, 1792, 870, 336, 116, 32, 10, 1024, 4624, 6624, 5040, 2632, 1117, 404, 134, 36, 11
Offset: 1

Views

Author

Geoffrey Critzer, Mar 08 2012

Keywords

Comments

Equivalently, T(n,k) is the number of partitions of the integer n with two types of 1's, four types of 2's, ..., 2^i types of i's...; having exactly k summands (of any type).
Row sums = A034899.

Examples

			Triangle T(n,k) begins:
    2;
    4,    3;
    8,    8,    4;
   16,   26,   12,    5;
   32,   64,   44,   16,   6;
   64,  164,  132,   62,  20,   7;
  128,  384,  376,  200,  80,  24,   8;
  256,  904, 1008,  623, 268,  98,  28,  9;
  512, 2048, 2632, 1792, 870, 336, 116, 32, 10;
  ...
		

Crossrefs

T(2n,n) gives A359962.

Programs

  • Maple
    b:= proc(n, i, p) option remember; `if`(p>n, 0, `if`(n=0, 1,
          `if`(min(i, p)<1, 0, add(b(n-i*j, i-1, p-j)*
           binomial(2^i+j-1, j), j=0..min(n/i, p)))))
        end:
    T:= (n, k)-> b(n$2, k):
    seq(seq(T(n, k), k=1..n), n=1..14);  # Alois P. Heinz, Apr 13 2017
  • Mathematica
    nn = 10; p[x_, y_] := Product[1/(1 - y x^i)^(2^i), {i, 1, nn}]; f[list_] := Select[lst, # > 0 &]; Map[f, Drop[CoefficientList[Series[p[x, y], {x, 0, nn}], {x, y}], 1]] // Flatten

Formula

O.g.f.: Product_{i>=1} 1/(1-y*x^i)^(2^i).

A290222 Multiset transform of A011782, powers of 2: 1, 2, 4, 8, 16, ...

Original entry on oeis.org

1, 0, 1, 0, 2, 1, 0, 4, 2, 1, 0, 8, 7, 2, 1, 0, 16, 16, 7, 2, 1, 0, 32, 42, 20, 7, 2, 1, 0, 64, 96, 54, 20, 7, 2, 1, 0, 128, 228, 140, 59, 20, 7, 2, 1, 0, 256, 512, 360, 156, 59, 20, 7, 2, 1, 0, 512, 1160, 888, 422, 162, 59, 20, 7, 2, 1, 0, 1024, 2560, 2168, 1088, 442, 162, 59, 20, 7, 2, 1
Offset: 0

Views

Author

M. F. Hasler, Jul 24 2017

Keywords

Comments

T(n,k) is the number of multisets of exactly k binary words with a total of n letters and each word beginning with 1. T(4,2) = 7: {1,100}, {1,101}, {1,110}, {1,111}, {10,10}, {10,11}, {11,11}. - Alois P. Heinz, Sep 18 2017

Examples

			The triangle starts:
1;
0    1;
0    2    1;
0    4    2    1;
0    8    7    2    1;
0   16   16    7    2   1;
0   32   42   20    7   2   1;
0   64   96   54   20   7   2  1;
0  128  228  140   59  20   7  2  1;
0  256  512  360  156  59  20  7  2  1;
0  512 1160  888  422 162  59 20  7  2  1;
0 1024 2560 2168 1088 442 162 59 20  7  2  1;
(...)
		

Crossrefs

Cf. A034691 (row sums), A000007 (column k=0), A011782 (column k=1), A178945(n-1) (column k=2).
The reverse of the n-th row converges to A034899.

Programs

  • Maple
    b:= proc(n, i, p) option remember; `if`(p>n, 0, `if`(n=0, 1,
          `if`(min(i, p)<1, 0, add(binomial(2^(i-1)+j-1, j)*
             b(n-i*j, i-1, p-j), j=0..min(n/i, p)))))
        end:
    T:= (n, k)-> b(n$2, k):
    seq(seq(T(n, k), k=0..n), n=0..14);  # Alois P. Heinz, Sep 12 2017
  • Mathematica
    b[n_, i_, p_] := b[n, i, p] = If[p > n, 0, If[n == 0, 1, If[Min[i, p] < 1, 0, Sum[Binomial[2^(i - 1) + j - 1, j] b[n - i j, i - 1, p - j], {j, 0, Min[n/i, p]}]]]];
    T[n_, k_] := b[n, n, k];
    Table[Table[T[n, k], {k, 0, n}], {n, 0, 14}] // Flatten (* Jean-François Alcover, Dec 07 2019, after Alois P. Heinz *)

Formula

G.f.: 1 / Product_{j>=1} (1-y*x^j)^(2^(j-1)). - Alois P. Heinz, Sep 18 2017

A292548 Number of multisets of nonempty binary words with a total of n letters such that no word has a majority of 0's.

Original entry on oeis.org

1, 1, 4, 8, 25, 53, 148, 328, 858, 1938, 4862, 11066, 27042, 61662, 147774, 336854, 795678, 1810466, 4228330, 9597694, 22211897, 50279985, 115489274, 260686018, 594986149, 1339215285, 3040004744, 6823594396, 15416270130, 34510814918, 77644149076, 173368564396
Offset: 0

Views

Author

Alois P. Heinz, Sep 18 2017

Keywords

Examples

			a(0) = 1: {}.
a(1) = 1: {1}.
a(2) = 4: {01}, {10}, {11}, {1,1}.
a(3) = 8: {011}, {101}, {110}, {111}, {1,01}, {1,10}, {1,11}, {1,1,1}.
		

Crossrefs

Row sums of A292506.
Column k=2 of A292712.
Cf. A027306.

Programs

  • Maple
    g:= n-> 2^(n-1)+`if`(n::odd, 0, binomial(n, n/2)/2):
    a:= proc(n) option remember; `if`(n=0, 1, add(add(d*
          g(d), d=numtheory[divisors](j))*a(n-j), j=1..n)/n)
        end:
    seq(a(n), n=0..35);
  • Mathematica
    g[n_] :=  2^(n-1) + If[OddQ[n], 0, Binomial[n, n/2]/2];
    a[n_] := a[n] = If[n == 0, 1, Sum[Sum[d*
         g[d], {d, Divisors[j]}]*a[n-j], {j, 1, n}]/n];
    Table[a[n], {n, 0, 35}] (* Jean-François Alcover, Apr 30 2022, after Alois P. Heinz *)

Formula

G.f.: Product_{j>=1} 1/(1-x^j)^A027306(j).
Euler transform of A027306.

A316403 Number of multisets of exactly two nonempty binary words with a total of n letters such that no word has a majority of 0's.

Original entry on oeis.org

1, 3, 10, 23, 59, 134, 320, 699, 1599, 3434, 7682, 16246, 35762, 74892, 163032, 338771, 731051, 1510466, 3237206, 6658530, 14189790, 29083988, 61687496, 126076638, 266332390, 543061284, 1143207236, 2326521164, 4882706596, 9920514328, 20764519984, 42130081155
Offset: 2

Views

Author

Alois P. Heinz, Jul 02 2018

Keywords

Examples

			a(4) = 10: {1,011}, {1,101}, {1,110}, {1,111}, {01,01}, {01,10}, {01,11}, {10,10}, {10,11}, {11,11}.
a(5) = 23: {1,0011}, {1,0101}, {1,0110}, {1,0111}, {1,1001}, {1,1010}, {1,1011}, {1,1100}, {1,1101}, {1,1110}, {1,1111}, {01,011}, {01,101}, {01,110}, {01,111}, {10,011}, {10,101}, {10,110}, {10,111}, {11,011}, {11,101}, {11,110}, {11,111}.
		

Crossrefs

Column k=2 of A292506.

Programs

  • Maple
    g:= n-> 2^(n-1)+`if`(n::odd, 0, binomial(n, n/2)/2):
    b:= proc(n, i) option remember; series(`if`(n=0 or i=1, x^n, add(
           binomial(g(i)+j-1, j)*b(n-i*j, i-1)*x^j, j=0..n/i)), x, 3)
        end:
    a:= n-> coeff(b(n$2), x, 2):
    seq(a(n), n=2..33);

Formula

a(n) = [x^n y^2] 1/Product_{j>=1} (1-y*x^j)^A027306(j).

A316404 Number of multisets of exactly three nonempty binary words with a total of n letters such that no word has a majority of 0's.

Original entry on oeis.org

1, 3, 10, 33, 83, 230, 568, 1451, 3439, 8384, 19390, 45708, 103770, 238855, 534400, 1208485, 2672043, 5959769, 13051586, 28792488, 62551270, 136760659, 295115360, 640444498, 1374092646, 2963283862, 6326402780, 13569867602, 28846140436, 61586022487, 130422459008
Offset: 3

Views

Author

Alois P. Heinz, Jul 02 2018

Keywords

Crossrefs

Column k=3 of A292506.

Programs

  • Maple
    g:= n-> 2^(n-1)+`if`(n::odd, 0, binomial(n, n/2)/2):
    b:= proc(n, i) option remember; series(`if`(n=0 or i=1, x^n, add(
           binomial(g(i)+j-1, j)*b(n-i*j, i-1)*x^j, j=0..n/i)), x, 4)
        end:
    a:= n-> coeff(b(n$2), x, 3):
    seq(a(n), n=3..33);

Formula

a(n) = [x^n y^3] 1/Product_{j>=1} (1-y*x^j)^A027306(j).

A316405 Number of multisets of exactly four nonempty binary words with a total of n letters such that no word has a majority of 0's.

Original entry on oeis.org

1, 3, 10, 33, 98, 270, 738, 1935, 5004, 12580, 31354, 76444, 185305, 441363, 1046837, 2447913, 5705753, 13143961, 30202325, 68719396, 156034994, 351348607, 789783351, 1762658134, 3928209272, 8700183502, 19244947618, 42340195770, 93049476310, 203518456343
Offset: 4

Views

Author

Alois P. Heinz, Jul 02 2018

Keywords

Crossrefs

Column k=4 of A292506.

Programs

  • Maple
    g:= n-> 2^(n-1)+`if`(n::odd, 0, binomial(n, n/2)/2):
    b:= proc(n, i) option remember; series(`if`(n=0 or i=1, x^n, add(
           binomial(g(i)+j-1, j)*b(n-i*j, i-1)*x^j, j=0..n/i)), x, 5)
        end:
    a:= n-> coeff(b(n$2), x, 4):
    seq(a(n), n=4..33);

Formula

a(n) = [x^n y^4] 1/Product_{j>=1} (1-y*x^j)^A027306(j).

A316406 Number of multisets of exactly five nonempty binary words with a total of n letters such that no word has a majority of 0's.

Original entry on oeis.org

1, 3, 10, 33, 98, 291, 798, 2200, 5804, 15275, 39014, 99214, 247065, 612090, 1492837, 3622213, 8682565, 20711303, 48923317, 115048586, 268374750, 623503251, 1438753371, 3307821910, 7560955644, 17225642730, 39047321794, 88249150462, 198572820286, 445610719629
Offset: 5

Views

Author

Alois P. Heinz, Jul 02 2018

Keywords

Crossrefs

Column k=5 of A292506.

Programs

  • Maple
    g:= n-> 2^(n-1)+`if`(n::odd, 0, binomial(n, n/2)/2):
    b:= proc(n, i) option remember; series(`if`(n=0 or i=1, x^n, add(
           binomial(g(i)+j-1, j)*b(n-i*j, i-1)*x^j, j=0..n/i)), x, 6)
        end:
    a:= n-> coeff(b(n$2), x, 5):
    seq(a(n), n=5..34);

Formula

a(n) = [x^n y^5] 1/Product_{j>=1} (1-y*x^j)^A027306(j).

A316407 Number of multisets of exactly six nonempty binary words with a total of n letters such that no word has a majority of 0's.

Original entry on oeis.org

1, 3, 10, 33, 98, 291, 826, 2284, 6185, 16471, 43156, 111446, 284517, 717486, 1793081, 4434929, 10887761, 26495243, 64069055, 153761086, 366992020, 870215947, 2053484109, 4818104922, 11256015936, 26164409278, 60583174348, 139655557194, 320805463602
Offset: 6

Views

Author

Alois P. Heinz, Jul 02 2018

Keywords

Crossrefs

Column k=6 of A292506.

Programs

  • Maple
    g:= n-> 2^(n-1)+`if`(n::odd, 0, binomial(n, n/2)/2):
    b:= proc(n, i) option remember; series(`if`(n=0 or i=1, x^n, add(
           binomial(g(i)+j-1, j)*b(n-i*j, i-1)*x^j, j=0..n/i)), x, 7)
        end:
    a:= n-> coeff(b(n$2), x, 6):
    seq(a(n), n=6..34);

Formula

a(n) = [x^n y^6] 1/Product_{j>=1} (1-y*x^j)^A027306(j).

A316408 Number of multisets of exactly seven nonempty binary words with a total of n letters such that no word has a majority of 0's.

Original entry on oeis.org

1, 3, 10, 33, 98, 291, 826, 2320, 6297, 16989, 44828, 117352, 302429, 773496, 1954845, 4905939, 12195457, 30123762, 73825711, 179891662, 435427632, 1048510795, 2510267189, 5981859208, 14182293004, 33482368279, 78690956088, 184229429914, 429570180998
Offset: 7

Views

Author

Alois P. Heinz, Jul 02 2018

Keywords

Crossrefs

Column k=7 of A292506.

Programs

  • Maple
    g:= n-> 2^(n-1)+`if`(n::odd, 0, binomial(n, n/2)/2):
    b:= proc(n, i) option remember; series(`if`(n=0 or i=1, x^n, add(
           binomial(g(i)+j-1, j)*b(n-i*j, i-1)*x^j, j=0..n/i)), x, 8)
        end:
    a:= n-> coeff(b(n$2), x, 7):
    seq(a(n), n=7..35);

Formula

a(n) = [x^n y^7] 1/Product_{j>=1} (1-y*x^j)^A027306(j).
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