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 12 results. Next

A214258 Number T(n,k) of compositions of n where the difference between largest and smallest parts equals k; triangle T(n,k), n>=1, 0<=k

Original entry on oeis.org

1, 2, 0, 2, 2, 0, 3, 3, 2, 0, 2, 9, 3, 2, 0, 4, 11, 12, 3, 2, 0, 2, 25, 20, 12, 3, 2, 0, 4, 35, 49, 23, 12, 3, 2, 0, 3, 60, 95, 58, 23, 12, 3, 2, 0, 4, 96, 188, 123, 61, 23, 12, 3, 2, 0, 2, 157, 366, 266, 132, 61, 23, 12, 3, 2, 0, 6, 241, 714, 557, 294, 135, 61, 23, 12, 3, 2, 0
Offset: 1

Views

Author

Alois P. Heinz, Jul 08 2012

Keywords

Comments

For fixed k > 0, limit_{n->infinity} T(n,k)^(1/n) = d, where d > 1 is the real root of the equation d^(k+2) - 2*d^(k+1) + 1 = 0. - Vaclav Kotesovec, Jan 07 2019

Examples

			T(4,0) = 3: [4], [2,2], [1,1,1,1].
T(5,1) = 9: [3,2], [2,3], [2,2,1], [2,1,2], [2,1,1,1], [1,2,2], [1,2,1,1], [1,1,2,1], [1,1,1,2].
T(5,2) = 3: [3,1,1], [1,3,1], [1,1,3].
T(5,3) = 2: [4,1], [1,4].
T(6,2) = 12: [4,2], [3,2,1], [3,1,2], [3,1,1,1], [2,4], [2,3,1], [2,1,3], [1,3,2], [1,3,1,1], [1,2,3], [1,1,3,1], [1,1,1,3].
Triangle T(n,k) begins:
  1;
  2,  0;
  2,  2,  0;
  3,  3,  2,  0;
  2,  9,  3,  2,  0;
  4, 11, 12,  3,  2,  0;
  2, 25, 20, 12,  3,  2,  0;
  4, 35, 49, 23, 12,  3,  2,  0;
		

Crossrefs

Programs

  • Maple
    b:= proc(n, k, s, t) option remember;
          `if`(n<0, 0, `if`(n=0, 1, add(b(n-j, k,
           min(s,j), max(t,j)), j=max(1, t-k+1)..s+k-1)))
        end:
    A:= proc(n, k) option remember;
          `if`(n=0, 1, add(b(n-j, k+1, j, j), j=1..n))
        end:
    T:= (n, k)-> A(n, k) -`if`(k=0, 0, A(n, k-1)):
    seq(seq(T(n,k), k=0..n-1), n=1..15);
    # second Maple program:
    b:= proc(n, s, t) option remember; `if`(n=0, x^(t-s),
          add(b(n-j, min(s, j), max(t, j)), j=1..n))
        end:
    T:= n-> (p-> seq(coeff(p, x, i), i=0..n-1))(b(n$2, 0)):
    seq(T(n), n=1..15);  # Alois P. Heinz, Jan 05 2019
  • Mathematica
    b[n_, k_, s_, t_] := b[n, k, s, t] = If[n < 0, 0, If[n == 0, 1, Sum [b[n-j, k, Min[s, j], Max[t, j]], {j, Max[1, t-k+1], s+k-1}]]]; A[n_, k_] := A[n, k] = If[n == 0, 1, Sum[b[n-j, k+1, j, j], {j, 1, n}]]; T[n_, k_] := A[n, k] - If[k == 0, 0, A[n, k-1]]; Table[Table[T[n, k], {k, 0, n-1}], {n, 1, 15}] // Flatten (* Jean-François Alcover, Jan 15 2014, translated from Maple *)

Formula

T(n,0) = A214257(n,0), T(n,k) = A214257(n,k)-A214257(n,k-1) for k>0.

A214269 Number T(n,k) of compositions of n where the difference between largest and smallest parts equals k and adjacent parts are unequal; triangle T(n,k), n>=1, 0<=k

Original entry on oeis.org

1, 1, 0, 1, 2, 0, 1, 1, 2, 0, 1, 3, 1, 2, 0, 1, 2, 8, 1, 2, 0, 1, 4, 7, 8, 1, 2, 0, 1, 2, 13, 12, 8, 1, 2, 0, 1, 4, 25, 18, 12, 8, 1, 2, 0, 1, 4, 27, 46, 23, 12, 8, 1, 2, 0, 1, 4, 43, 69, 51, 23, 12, 8, 1, 2, 0, 1, 3, 71, 111, 90, 56, 23, 12, 8, 1, 2, 0
Offset: 1

Views

Author

Alois P. Heinz, Jul 09 2012

Keywords

Examples

			T(7,0) = 1: [7].
T(7,1) = 4: [4,3], [3,4], [2,3,2], [1,2,1,2,1].
T(7,2) = 7: [3,1,3], [3,1,2,1], [2,1,3,1], [1,3,2,1], [1,3,1,2], [1,2,3,1], [1,2,1,3].
T(7,3) = 8: [5,2], [4,2,1], [4,1,2], [2,5], [2,4,1], [2,1,4], [1,4,2], [1,2,4].
T(7,4) = 1: [1,5,1].
T(7,5) = 2: [6,1], [1,6].
Triangle T(n,k) begins:
  1;
  1,  0;
  1,  2,  0;
  1,  1,  2,  0;
  1,  3,  1,  2,  0;
  1,  2,  8,  1,  2,  0;
  1,  4,  7,  8,  1,  2,  0;
  1,  2, 13, 12,  8,  1,  2,  0;
		

Crossrefs

Programs

  • Maple
    b:= proc(n, k, s, t, l) option remember;
          `if`(n<0, 0, `if`(n=0, 1, add(`if`(j=l, 0, b(n-j, k,
           min(s, j), max(t, j), j)), j=max(1, t-k+1)..s+k-1)))
        end:
    A:= proc(n, k) option remember;
          `if`(n=0, 1, add(b(n-j, k+1, j, j, j), j=1..n))
        end:
    T:= (n, k)-> A(n, k) -`if`(k=0, 0, A(n, k-1)):
    seq(seq(T(n, k), k=0..n-1), n=1..14);
  • Mathematica
    b[n_, k_, s_, t_, l_] := b[n, k, s, t, l] = If[n < 0, 0, If[n == 0, 1, Sum [If[j == l, 0, b[n-j, k, Min[s, j], Max[t, j], j]], {j, Max[1, t-k+1], s+k-1}] ] ]; a[n_, k_] := a[n, k] = If[n == 0, 1, Sum[b[n - j, k+1, j, j, j], {j, 1, n}]]; t[n_, k_] := a[n, k] - If[k == 0, 0, a[n, k-1]]; Table[Table[t[n, k], {k, 0, n-1}], {n, 1, 12}] // Flatten (* Jean-François Alcover, Dec 11 2013, translated from Maple *)

Formula

T(n,0) = 1, T(n,k) = A214268(n,k) - A214268(n,k-1) for k>0.

A034297 Number of ordered positive integer solutions (m_1, m_2, ..., m_k) (for some k) to Sum_{i=1..k} m_i=n with |m_i-m_{i-1}| <= 1 for i = 2 ... k.

Original entry on oeis.org

1, 1, 2, 4, 6, 11, 17, 29, 47, 78, 130, 215, 357, 595, 990, 1651, 2748, 4584, 7643, 12744, 21256, 35451, 59133, 98636, 164531, 274463, 457837, 763746, 1274060, 2125356, 3545491, 5914545, 9866602, 16459421, 27457549, 45804648, 76411272, 127469285, 212644336
Offset: 0

Views

Author

Keywords

Comments

Compositions of n where successive parts differ by at most 1, see example. [Joerg Arndt, Dec 10 2012]

Examples

			From _Joerg Arndt_, Dec 10 2012: (Start)
The a(6) = 17 such compositions of 6 are
[ #]     composition
[ 1]    [ 1 1 1 1 1 1 ]
[ 2]    [ 1 1 1 1 2 ]
[ 3]    [ 1 1 1 2 1 ]
[ 4]    [ 1 1 2 1 1 ]
[ 5]    [ 1 1 2 2 ]
[ 6]    [ 1 2 1 1 1 ]
[ 7]    [ 1 2 1 2 ]
[ 8]    [ 1 2 2 1 ]
[ 9]    [ 1 2 3 ]
[10]    [ 2 1 1 1 1 ]
[11]    [ 2 1 1 2 ]
[12]    [ 2 1 2 1 ]
[13]    [ 2 2 1 1 ]
[14]    [ 2 2 2 ]
[15]    [ 3 2 1 ]
[16]    [ 3 3 ]
[17]    [ 6 ]
(End)
		

Crossrefs

Column k=1 of A214246, A214248.
Row sums of A309939.

Programs

  • Maple
    b:= proc(n, i) option remember;
          `if`(n=i, 1, `if`(n<0 or i<1, 0, add(b(n-i, i+j), j=-1..1)))
        end:
    a:= n-> add(b(n, k), k=0..n):
    seq(a(n), n=0..50);  # Alois P. Heinz, Jul 06 2012
  • Mathematica
    b[n_, i_] := b[n, i] = If[n == i, 1, If[n<0 || i<1, 0, Sum[b[n-i, i+j], {j, -1, 1}] ]]; a[n_] := Sum[b[n, k], {k, 1, n}]; Array[a, 50] (* Jean-François Alcover, Mar 13 2015, after Alois P. Heinz *)
  • PARI
    N=70;  nil=-1;
    T = matrix(N, N, i, j, nil);
    doIt(last, left) = my(c); c = T[last, left]; if (c == nil, c = 0; for (i = max(1, last - 1), last + 1, c += b(i, left - i)); T[last, left] = c); c;
    b(last, left) = if (left == 0, return(1)); if (left < 0, return(0)); doIt(last, left);
    a(n) = sum (i = 1, n, b(i, n - i));
    vector(N,n,a(n))  \\ David Wasserman, Feb 02 2006
    
  • Python
    from sympy.core.cache import cacheit
    @cacheit
    def b(n, i): return 1 if n==i else 0 if n<0 or i<1 else sum(b(n - i, i + j) for j in range(-1, 2))
    def a(n): return sum(b(n, k) for k in range(n + 1))
    print([a(n) for n in range(51)]) # Indranil Ghosh, Aug 14 2017, after Maple code

Formula

a(n) ~ c * d^n, where d = 1.668202067018461116361070469945501401879811945303435230637248..., c = 0.762436680050402638439806786781869262562176911054246754543346... . - Vaclav Kotesovec, Sep 02 2014

Extensions

More terms from David Wasserman, Feb 02 2006
a(0)=1 prepended by Alois P. Heinz, Aug 14 2017

A214247 Number A(n,k) of compositions of n where differences between neighboring parts are in {-k,k}; square array A(n,k), n>=0, k>=0, read by antidiagonals.

Original entry on oeis.org

1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 3, 3, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 3, 4, 4, 1, 1, 1, 1, 1, 2, 5, 2, 1, 1, 1, 1, 1, 3, 3, 5, 4, 1, 1, 1, 1, 1, 1, 2, 2, 7, 3, 1, 1, 1, 1, 1, 1, 3, 3, 6, 10, 4, 1, 1, 1, 1, 1, 1, 1, 2, 1, 4, 9, 2
Offset: 0

Views

Author

Alois P. Heinz, Jul 08 2012

Keywords

Examples

			A(5,0) = 2: [5], [1,1,1,1,1].
A(5,1) = 4: [5], [3,2], [2,3], [2,1,2].
A(5,2) = 2: [5], [1,3,1].
A(5,3) = 3: [5], [4,1], [1,4].
Square array A(n,k) begins:
  1,  1,  1,  1,  1,  1,  1,  1,  1, ...
  1,  1,  1,  1,  1,  1,  1,  1,  1, ...
  2,  1,  1,  1,  1,  1,  1,  1,  1, ...
  2,  3,  1,  1,  1,  1,  1,  1,  1, ...
  3,  2,  3,  1,  1,  1,  1,  1,  1, ...
  2,  4,  2,  3,  1,  1,  1,  1,  1, ...
  4,  5,  3,  2,  3,  1,  1,  1,  1, ...
  2,  5,  2,  3,  2,  3,  1,  1,  1, ...
  4,  7,  6,  1,  3,  2,  3,  1,  1, ...
		

Crossrefs

Columns k=0-2 give: A000005, A173258, A214254.
Rows n=0, 1 and main diagonal give: A000012.

Programs

  • Maple
    b:= proc(n, i, k) option remember;
          `if`(n<1 or i<1, 0, `if`(n=i, 1, add(b(n-i, i+j, k), j={-k, k})))
        end:
    A:= (n, k)-> `if`(n=0, 1, add(b(n, j, k), j=1..n)):
    seq(seq(A(n, d-n), n=0..d), d=0..15);
  • Mathematica
    b[n_, i_, k_] := b[n, i, k] = If[n < 1 || i < 1, 0, If[n == i, 1, Sum[b[n - i, i + j, k], { j, Union[{-k, k}]}]]]; a[n_, k_] := If[n == 0, 1, Sum[b[n, j, k], {j, 1, n}]]; Table[Table[a[n, d - n], {n, 0, d}], {d, 0, 15}] // Flatten (* Jean-François Alcover, Dec 13 2013, translated from Maple *)
  • PARI
    tri(k) = {(k*(k+1)/2)}
    ra(n) = {(sqrt(1+8*n)-1)/2}
    C(q,n) = {c = if(n<=1, return(1)); return(sum(i=0, n-1, C(q, i) * C(q, n-1-i) * q^((i+1)*(n-1 -i))));}
    Cw_q(i,k) = {return(q^(((k+2)*i)+1) * polrecip(C(q^(2*k),i)))}
    A_qt(k,N) = {1 + sum(i=0,N/(k+1), t^((2*i)+1) * Cw_q(i,k) * (sum(j=0,ra(N+2)+1, prod(u=1,j, sum(v=0,(N-(tri(u)*k))/(k+2), t^((2*v)+1) * q^(((2*v)+1)*u*k) * Cw_q(v,k)))))^2)}
    A_q(k,N) = {my(q='q+O('q^N), Aqt = A_qt(k,N), Aq = 1); for(i=1,poldegree(Aqt,t), Aq += polcoef(Aqt,i,t)/(1-q^i)); Aq}
    A214247_array(maxrow,maxcolumn) = {my(m=concat([1],vector(maxrow,n,numdiv(n)))~); for(k=1,maxcolumn, m = matconcat([m,Vec(A_q(k,maxrow))~])); m}
    A214247_array(10,10) \\ John Tyler Rascoe, Oct 15 2024

Formula

G.f. for column k > 0: A(k,q) is A(k,q,t) = Sum_{n,m>=0} (q^n)*(t^m) under the transform (q^n)*(t^m) -> (q^n)/(1-q^m) for all m > 0 where A(k,q,t) = 1 + Sum_{i>=0} ( t^((2*i)+1) * Cw(i,k,q) * (Sum_{j>=0} (Product_{u=1..j} (Sum_{v>=0} t^((2*v)+1) * q^(((2*v)+1)*k*u) * Cw(v,k,q))))^2 ), Cw(i,k,q) = q^(((k+2)*i)+1) * Ca(i,q^(2*k)), and Ca(i,q) is the i-th Carlitz-Riordan q-Catalan number (i-th row polynomial of A227543). - John Tyler Rascoe, Sep 13 2024

A214249 Number A(n,k) of compositions of n where differences between neighboring parts are in {-k,...,k} \ {0}; square array A(n,k), n>=0, k>=0, read by antidiagonals.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 3, 2, 1, 1, 1, 1, 3, 4, 4, 1, 1, 1, 1, 3, 4, 5, 5, 1, 1, 1, 1, 3, 4, 7, 11, 5, 1, 1, 1, 1, 3, 4, 7, 12, 14, 7, 1, 1, 1, 1, 3, 4, 7, 14, 20, 18, 10, 1, 1, 1, 1, 3, 4, 7, 14, 21, 30, 36, 9, 1, 1, 1, 1, 3, 4, 7, 14, 23, 36, 50, 49, 14, 1
Offset: 0

Views

Author

Alois P. Heinz, Jul 08 2012

Keywords

Examples

			A(3,0) = 1: [3].
A(4,1) = 2: [4], [1,2,1].
A(5,2) = 5: [5], [3,2], [2,3], [2,1,2], [1,3,1].
A(6,3) = 12: [6], [4,2], [3,2,1], [3,1,2], [2,4], [2,3,1], [2,1,3], [2,1,2,1], [1,4,1], [1,3,2], [1,2,3], [1,2,1,2].
Square array A(n,k) begins:
  1,  1,  1,  1,  1,  1,  1,  1, ...
  1,  1,  1,  1,  1,  1,  1,  1, ...
  1,  1,  1,  1,  1,  1,  1,  1, ...
  1,  3,  3,  3,  3,  3,  3,  3, ...
  1,  2,  4,  4,  4,  4,  4,  4, ...
  1,  4,  5,  7,  7,  7,  7,  7, ...
  1,  5, 11, 12, 14, 14, 14, 14, ...
  1,  5, 14, 20, 21, 23, 23, 23, ...
		

Crossrefs

Columns k=0-2 give: A000012, A173258, A214256.
Main diagonal gives: A003242.

Programs

  • Maple
    b:= proc(n, i, k) option remember; `if`(n<1 or i<1, 0,
          `if`(n=i, 1, add(b(n-i, i+j, k), j={$-k..k} minus{0})))
        end:
    A:= (n, k)-> `if`(n=0, 1, add(b(n, j, min(n, k)), j=1..n)):
    seq(seq(A(n, d-n), n=0..d), d=0..15);
  • Mathematica
    b[n_, i_, k_] := b[n, i, k] = If[n<1 || i<1, 0, If[n == i, 1, Sum[b[n-i, i+j, k], {j, Range[-k, -1] ~Join~ Range[k]}]]]; A[n_, k_] := If[n == 0, 1, Sum[b[n, j, Min[n, k]], {j, 1, n}]]; Table[Table[A[n, d-n], {n, 0, d}], {d, 0, 15}] // Flatten (* Jean-François Alcover, Jan 15 2014, translated from Maple *)

A214246 Number A(n,k) of compositions of n where differences between neighboring parts are in {-k,0,k}; square array A(n,k), n>=0, k>=0, read by antidiagonals.

Original entry on oeis.org

1, 1, 1, 1, 1, 2, 1, 1, 2, 2, 1, 1, 2, 4, 3, 1, 1, 2, 2, 6, 2, 1, 1, 2, 2, 5, 11, 4, 1, 1, 2, 2, 3, 5, 17, 2, 1, 1, 2, 2, 3, 4, 10, 29, 4, 1, 1, 2, 2, 3, 2, 7, 10, 47, 3, 1, 1, 2, 2, 3, 2, 6, 8, 21, 78, 4, 1, 1, 2, 2, 3, 2, 4, 5, 9, 22, 130, 2
Offset: 0

Views

Author

Alois P. Heinz, Jul 08 2012

Keywords

Examples

			A(3,0) = 2: [3], [1,1,1].
A(4,1) = 6: [4], [2,2], [2,1,1], [1,2,1], [1,1,2], [1,1,1,1].
A(5,2) = 5: [5], [3,1,1], [1,3,1], [1,1,3], [1,1,1,1,1].
A(6,3) = 7: [6], [4,1,1], [3,3], [2,2,2], [1,4,1], [1,1,4], [1,1,1,1,1,1].
Square array A(n,k) begins:
  1,  1,  1,  1,  1,  1,  1,  1, ...
  1,  1,  1,  1,  1,  1,  1,  1, ...
  2,  2,  2,  2,  2,  2,  2,  2, ...
  2,  4,  2,  2,  2,  2,  2,  2, ...
  3,  6,  5,  3,  3,  3,  3,  3, ...
  2, 11,  5,  4,  2,  2,  2,  2, ...
  4, 17, 10,  7,  6,  4,  4,  4, ...
  2, 29, 10,  8,  5,  4,  2,  2, ...
		

Crossrefs

Column k=0 and main diagonal give: A000005.
Columns k=1, 2 give: A034297, A214253.

Programs

  • Maple
    b:= proc(n, i, k) option remember;
          `if`(n<1 or i<1, 0, `if`(n=i, 1, add(b(n-i, i+j, k), j={-k, 0, k})))
        end:
    A:= (n, k)-> `if`(n=0, 1, add(b(n, j, k), j=1..n)):
    seq(seq(A(n, d-n), n=0..d), d=0..15);
  • Mathematica
    b[n_, i_, k_] := b[n, i, k] = If[n < 1 || i < 1, 0, If[n == i, 1, Sum[b[n - i, i + j, k], {j, Union[{-k, 0, k}]}]]]; A[n_, k_] := If[n == 0, 1, Sum[b[n, j, k], {j, 1, n}]]; Table[Table[A[n, d - n], {n, 0, d}], {d, 0, 15}] // Flatten (* Jean-François Alcover, Dec 27 2013, translated from Maple *)

A215025 Decimal equivalent of binary number in A215023.

Original entry on oeis.org

0, 2, 9, 8, 10, 37, 36, 33, 32, 34, 41, 40, 42, 149, 148, 145, 144, 146, 133, 132, 129, 128, 130, 137, 136, 138, 165, 164, 161, 160, 162, 169, 168, 170, 597, 596, 593, 592, 594, 581, 580, 577, 576, 578, 585, 584, 586, 533, 532, 529, 528, 530, 517, 516, 513, 512
Offset: 0

Views

Author

N. J. A. Sloane, Aug 03 2012

Keywords

Crossrefs

Programs

  • Mathematica
    ind[n_] := Floor[Log[Abs[n]*Sqrt[5] + 1/2]/Log[GoldenRatio]]; f[1] = 1; f[n_] := If[n > 0, i = ind[n - 1]; If[EvenQ[i], i++]; i, i = ind[-n]; If[OddQ[i], i++]; i]; a[n_] := Module[{k = n, s = 0}, While[k != 0, i = f[k]; s += 2^(i - 1); k -= Fibonacci[-i]]; s]; Table[a[n], {n, 0, -100, -1}] (* Amiram Eldar, Oct 15 2019 *)

Extensions

More terms from Amiram Eldar, Oct 11 2019

A214257 Number A(n,k) of compositions of n where the difference between largest and smallest parts is <= k; square array A(n,k), n>=0, k>=0, read by antidiagonals.

Original entry on oeis.org

1, 1, 1, 1, 1, 2, 1, 1, 2, 2, 1, 1, 2, 4, 3, 1, 1, 2, 4, 6, 2, 1, 1, 2, 4, 8, 11, 4, 1, 1, 2, 4, 8, 14, 15, 2, 1, 1, 2, 4, 8, 16, 27, 27, 4, 1, 1, 2, 4, 8, 16, 30, 47, 39, 3, 1, 1, 2, 4, 8, 16, 32, 59, 88, 63, 4, 1, 1, 2, 4, 8, 16, 32, 62, 111, 158, 100, 2
Offset: 0

Views

Author

Alois P. Heinz, Jul 08 2012

Keywords

Examples

			A(3,0) =  2: [3], [1,1,1].
A(4,1) =  6: [4], [2,2], [2,1,1], [1,2,1], [1,1,2], [1,1,1,1].
A(5,1) =  8: [5], [3,2], [2,3], [2,2,1], [2,1,2], [2,1,1,1], [1,2,2], [1,2,1,1], [1,1,2,1], [1,1,1,2], [1,1,1,1,1],
A(5,2) = 14: [5], [3,2], [3,1,1], [2,3], [2,2,1], [2,1,2], [2,1,1,1], [1,3,1], [1,2,2], [1,2,1,1], [1,1,3], [1,1,2,1], [1,1,1,2], [1,1,1,1,1].
Square array A(n,k) begins:
  1,  1,  1,  1,  1,  1,  1,  1, ...
  1,  1,  1,  1,  1,  1,  1,  1, ...
  2,  2,  2,  2,  2,  2,  2,  2, ...
  2,  4,  4,  4,  4,  4,  4,  4, ...
  3,  6,  8,  8,  8,  8,  8,  8, ...
  2, 11, 14, 16, 16, 16, 16, 16, ...
  4, 15, 27, 30, 32, 32, 32, 32, ...
  2, 27, 47, 59, 62, 64, 64, 64, ...
		

Crossrefs

Columns k=0-1 give: A000005, A072951.
Main diagonal gives: A011782.

Programs

  • Maple
    b:= proc(n, k, s, t) option remember;
          `if`(n<0, 0, `if`(n=0, 1, add(b(n-j, k,
           min(s,j), max(t,j)), j=max(1, t-k+1)..s+k-1)))
        end:
    A:= (n, k)-> `if`(n=0, 1, add(b(n-j, k+1, j, j), j=1..n)):
    seq(seq(A(n, d-n), n=0..d), d=0..11);
    # second Maple program:
    b:= proc(n, s, t) option remember; `if`(n=0, x^(t-s),
          add(b(n-j, min(s, j), max(t, j)), j=1..n))
        end:
    T:= (n, k)-> coeff(b(n$2, 0), x, k):
    A:= proc(n, k) option remember; `if`(k<0, 0,
          `if`(k>n, A(n$2), A(n, k-1)+T(n, k)))
        end:
    seq(seq(A(n, d-n), n=0..d), d=0..11);  # Alois P. Heinz, Jan 05 2019
  • Mathematica
    b[n_, k_, s_, t_] := b[n, k, s, t] = If[n < 0, 0, If[n == 0, 1, Sum [b[n - j, k, Min[s, j], Max[t, j]], {j, Max[1, t - k + 1], s + k - 1}]]]; A[n_, k_] := If[n == 0, 1, Sum[b[n - j, k + 1, j, j], {j, 1, n}]]; Table[Table[A[n, d - n], {n, 0, d}], {d, 0, 11}] // Flatten (* Jean-François Alcover, Dec 27 2013, translated from Maple *)

Formula

T(n,k) = Sum_{i=0..k} A214258(n,i).

A214268 Number A(n,k) of compositions of n where the difference between largest and smallest parts is <= k and adjacent parts are unequal; square array A(n,k), n>=0, k>=0, read by antidiagonals.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 3, 2, 1, 1, 1, 1, 3, 4, 4, 1, 1, 1, 1, 3, 4, 5, 3, 1, 1, 1, 1, 3, 4, 7, 11, 5, 1, 1, 1, 1, 3, 4, 7, 12, 12, 3, 1, 1, 1, 1, 3, 4, 7, 14, 20, 16, 5, 1, 1, 1, 1, 3, 4, 7, 14, 21, 28, 30, 5, 1
Offset: 0

Views

Author

Alois P. Heinz, Jul 09 2012

Keywords

Examples

			A(3,0) = 1: [3].
A(4,1) = 2: [4], [1,2,1].
A(5,2) = 5: [5], [3,2], [2,3], [2,1,2], [1,3,1].
A(6,3) = 12: [6], [4,2], [3,2,1], [3,1,2], [2,4], [2,3,1], [2,1,3], [2,1,2,1], [1,4,1], [1,3,2], [1,2,3], [1,2,1,2].
A(7,4) = 21: [7], [5,2], [4,3], [4,2,1], [4,1,2], [3,4], [3,1,3], [3,1,2,1], [2,5], [2,4,1], [2,3,2], [2,1,4], [2,1,3,1], [1,5,1], [1,4,2], [1,3,2,1], [1,3,1,2], [1,2,4], [1,2,3,1], [1,2,1,3], [1,2,1,2,1].
Square array A(n,k) begins:
  1,  1,  1,  1,  1,  1,  1,  1, ...
  1,  1,  1,  1,  1,  1,  1,  1, ...
  1,  1,  1,  1,  1,  1,  1,  1, ...
  1,  3,  3,  3,  3,  3,  3,  3, ...
  1,  2,  4,  4,  4,  4,  4,  4, ...
  1,  4,  5,  7,  7,  7,  7,  7, ...
  1,  3, 11, 12, 14, 14, 14, 14, ...
  1,  5, 12, 20, 21, 23, 23, 23, ...
		

Crossrefs

Columns k=0, 1 give: A000012, 1+A214270(n).
Main diagonal gives: A003242.

Programs

  • Maple
    b:= proc(n, k, s, t, l) option remember;
          `if`(n<0, 0, `if`(n=0, 1, add(`if`(j=l, 0, b(n-j, k,
           min(s, j), max(t, j), j)), j=max(1, t-k+1)..s+k-1)))
        end:
    A:= (n, k)-> `if`(n=0, 1, add(b(n-j, k+1, j, j, j), j=1..n)):
    seq(seq(A(n,d-n), n=0..d), d=0..14);
  • Mathematica
    b[n_, k_, s_, t_, l_] := b[n, k, s, t, l] = If[n < 0, 0, If[n == 0, 1, Sum[If[j == l, 0, b[n - j, k, Min[s, j], Max[t, j], j]], {j, Max[1, t - k + 1], s + k - 1}]]]; A[n_, k_] := If[n == 0, 1, Sum[b[n - j, k + 1, j, j, j], {j, 1, n}]]; Table[Table[A [n, d - n], {n, 0, d}], {d, 0, 14}] // Flatten (* Jean-François Alcover, Dec 27 2013, translated from Maple *)

A215024 Decimal equivalent of binary number in A215022.

Original entry on oeis.org

0, 1, 4, 5, 18, 16, 17, 20, 21, 74, 72, 73, 66, 64, 65, 68, 69, 82, 80, 81, 84, 85, 298, 296, 297, 290, 288, 289, 292, 293, 266, 264, 265, 258, 256, 257, 260, 261, 274, 272, 273, 276, 277, 330, 328, 329, 322, 320, 321, 324, 325, 338, 336, 337, 340, 341, 1194
Offset: 0

Views

Author

N. J. A. Sloane, Aug 03 2012

Keywords

Crossrefs

Programs

  • Mathematica
    ind[n_] := Floor[Log[Abs[n]*Sqrt[5] + 1/2]/Log[GoldenRatio]]; f[1] = 1; f[n_] := If[n > 0, i = ind[n - 1]; If[EvenQ[i], i++]; i, i = ind[-n]; If[OddQ[i], i++]; i]; a[n_] := Module[{k = n, s = 0}, While[k != 0, i = f[k]; s += 2^(i - 1); k -= Fibonacci[-i]]; s]; Array[a, 100, 0] (* Amiram Eldar, Oct 15 2019 *)
  • PARI
    a(n)=if(n<2,return(n));my(s=1,k=1,v);while(sCharles R Greathouse IV, Aug 03 2012 [Caution: returns wrong values for some values of n > 15. Amiram Eldar, Oct 15 2019]

Extensions

Data corrected by Amiram Eldar, Oct 11 2019
Showing 1-10 of 12 results. Next