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 62 results. Next

A024326 a(n) = s(1)*t(n) + s(2)*t(n-1) + ... + s(k)*t(n+1-k), where k = floor((n+1)/2), s = A023531, t = A023533.

Original entry on oeis.org

0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 2, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 1
Offset: 1

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Author

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 120;
    A023533:= A023533 = With[{ms= Table[m(m+1)(m+2)/6, {m, 0, nmax+5}]}, Table[If[MemberQ[ms, n], 1, 0], {n, 0, nmax+5}]];
    AbsoluteTiming[Table[t=0; m=3; p=BitShiftRight[n]; n--; While[n>p, t += A023533[[n + 1]]; n -= m++]; t, {n, nmax}]] (* G. C. Greubel, Jan 29 2022  *)
  • Sage
    nmax=120
    @CachedFunction
    def A023531(n):
        if ((sqrt(8*n+9) -3)/2).is_integer(): return 1
        else: return 0
    @CachedFunction
    def B_list(N):
        A = []
        for m in range(ceil((6*N)^(1/3))):
            A.extend([0]*(binomial(m+2, 3) -len(A)) +[1])
        return A
    A023533 = B_list(nmax+5)
    @CachedFunction
    def A023324(n): return sum( A023531(j)*A023533[n-j+1] for j in (1..((n+1)//2)) )
    [A023324(n) for n in (1..nmax)] # G. C. Greubel, Jan 29 2022

Formula

a(n) = Sum_{j=1..floor((n+1)/2)} A023531(j)*A023533(n-j+1).

A023670 Convolution of A023533 with itself.

Original entry on oeis.org

1, 0, 0, 2, 0, 0, 1, 0, 0, 2, 0, 0, 2, 0, 0, 0, 0, 0, 1, 2, 0, 0, 2, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 2, 0, 0, 2, 1, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 2, 0, 0, 2, 0, 0, 0, 0, 0, 2, 0, 0, 0, 1, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 2, 0, 0, 2
Offset: 1

Views

Author

Keywords

Crossrefs

Cf. A023533.

Programs

Formula

a(n) = Sum_{k=1..n} A023533(k)*A023533(n-k+1). - G. C. Greubel, Jul 14 2022

A024692 a(n) = s(1)s(n) + s(2)s(n-1) + ... + s(k)s(n+1-k), where k = floor((n+1)/2), s = A023533.

Original entry on oeis.org

1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1
Offset: 1

Views

Author

Keywords

Crossrefs

Cf. A023533.

Programs

Formula

a(n) = Sum_{k=1..floor((n+1)/2)} A023533(k)*A023533(n-k+1).

A023613 Convolution of Fibonacci numbers and A023533.

Original entry on oeis.org

1, 1, 2, 4, 6, 10, 16, 26, 42, 69, 111, 180, 291, 471, 762, 1233, 1995, 3228, 5223, 8452, 13675, 22127, 35802, 57929, 93731, 151660, 245391, 397051, 642442, 1039493, 1681935, 2721428, 4403363, 7124791
Offset: 0

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Author

Keywords

Crossrefs

Programs

  • Magma
    A023533:= func< n | Binomial(Floor((6*n-1)^(1/3)) +2, 3) ne n select 0 else 1 >;
    [(&+[Fibonacci(k)*A023533(n+2-k): k in [1..n+1]]): n in [0..50]]; // G. C. Greubel, Jul 14 2022
  • Mathematica
    Join[{1,1}, Table[Sum[Fibonacci[m+2 -Binomial[j+3,3]], {j,0,n}], {n,6}, {m, Binomial[n+3,3] -2, Binomial[n+4,3] -3}]]//Flatten (* G. C. Greubel, Jul 14 2022 *)
  • Sage
    #Assuming A023533 is available as an array
    for n in range(34):
        print(n, sum([A023533[k]*fibonacci(n+2-k) for k in range(1,n+2)]))
    # Danny Rorabaugh, Mar 14 2015
    

Formula

a(n) = Sum_{k=1..n+1} A000045(k)*A023533(n+2-k). - Danny Rorabaugh, Mar 13 2015

A024595 a(n) = s(1)*t(n) + s(2)*t(n-1) + ... + s(k)*t(n+1-k), where k = floor((n+1)/2), s = (F(2), F(3), ...), t = A023533.

Original entry on oeis.org

1, 0, 0, 1, 2, 3, 5, 0, 0, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1598, 2586, 4184, 6770, 10954, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765, 10946, 17711, 28658, 46370, 75028, 121398, 196426
Offset: 1

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Author

Keywords

Crossrefs

Programs

  • Magma
    A023533:= func< n | Binomial(Floor((6*n-1)^(1/3)) +2, 3) ne n select 0 else 1 >;
    [(&+[Fibonacci(k+1)*A023533(n-k+1): k in [1..Floor((n+1)/2)]]): n in [1..100]]; // G. C. Greubel, Jul 14 2022
    
  • Mathematica
    A023533[n_]:= If[Binomial[Floor[Surd[6*n-1, 3]] +2, 3] != n, 0, 1];
    A024595[n_]:= A024595[n]= Sum[Fibonacci[k+1]*A023533[n+1-k], {k, Floor[(n+1)/2]}];
    Table[A024595[n], {n,100}] (* G. C. Greubel, Jul 14 2022 *)
  • SageMath
    def A023533(n):
        if binomial( floor( (6*n-1)^(1/3) ) +2, 3) != n: return 0
        else: return 1
    [sum(fibonacci(k+1)*A023533(n-k+1) for k in (1..((n+1)//2))) for n in (1..100)] # G. C. Greubel, Jul 14 2022

Formula

a(n) = Sum_{k=1..floor((n+1)/2)} Fibonacci(k+1)*A023533(n-k+1).

A023543 Convolution of natural numbers with A023533.

Original entry on oeis.org

1, 2, 3, 5, 7, 9, 11, 13, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42, 45, 49, 53, 57, 61, 65, 69, 73, 77, 81, 85, 89, 93, 97, 101, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, 175, 180, 185, 190, 195, 200, 205, 210, 216, 222, 228
Offset: 1

Views

Author

Keywords

Crossrefs

Programs

  • Magma
    A023533:= func< n | Binomial(Floor((6*n-1)^(1/3)) +2, 3) ne n select 0 else 1 >;
    [(&+[A023533(k)*(n+1-k): k in [1..Floor((n+1)/2)]]): n in [1..100]]; // G. C. Greubel, Jul 15 2022
    
  • Mathematica
    Join[{1,2}, Table[(m+2)*(n+1) -Binomial[n+4,4], {n,6}, {m, Binomial[n+3,3] -2, Binomial[n+4,3] -3}]]//Flatten (* G. C. Greubel, Jul 15 2022 *)
  • SageMath
    [1,2]+flatten([[(m+2)*(n+1) - binomial(n+4,4) for m in (binomial(n+3,3)-2 .. binomial(n+4,3)-3)] for n in (1..6)]) # G. C. Greubel, Jul 15 2022

Formula

From G. C. Greubel, Jul 15 2022: (Start)
a(n) = Sum_{j=1..floor((n+1)/2)} (n - j + 1)*A023533(j).
a(n) = (m+2)*(n+1) - binomial(n+4, 4), for binomial(n+3, 3) - 2 <= m <= binomial(n+4, 3) - 3, and n >= 1, with a(1) = 1, a(2) = 2. (End)

Extensions

Title updated by Sean A. Irvine, Jun 06 2019

A023665 Convolution of A000201 and A023533.

Original entry on oeis.org

1, 3, 4, 7, 11, 13, 17, 20, 23, 28, 32, 37, 43, 47, 52, 57, 61, 67, 71, 77, 84, 90, 97, 103, 109, 117, 122, 129, 136, 141, 149, 155, 161, 169, 175, 184, 192, 199, 209, 215, 224, 232, 240, 249, 256, 264, 274, 280, 289, 297, 304, 314, 321, 329, 337
Offset: 1

Views

Author

Keywords

Crossrefs

Programs

  • Magma
    A023533:= func< n | Binomial(Floor((6*n-1)^(1/3)) +2, 3) ne n select 0 else 1 >;
    [(&+[Floor(k*(1+Sqrt(5))/2)*A023533(n-k+1): k in [1..n]]): n in [1..80]]; // G. C. Greubel, Jul 18 2022
    
  • Mathematica
    Table[Sum[Floor[(k+1 +Binomial[n+2,3] -Binomial[j+2,3])*GoldenRatio], {j,n}], {n, 7}, {k,0,n*(n+3)/2}] (* G. C. Greubel, Jul 18 2022 *)
  • SageMath
    def A023665(n, k): return sum( floor((k+1 + binomial(n+2,3) - binomial(j+2,3))*golden_ratio) for j in (1..n) )
    flatten([[A023665(n,k) for k in (0..n*(n+3)/2)] for n in (1..7)]) # G. C. Greubel, Jul 18 2022

Formula

a(n) = Sum_{j=1..n} A000201(j) * A023533(n-j+1).
T(n, k) = Sum_{j=1..n} A000201(k+1 +binomial(n+2,3) -binomial(j+2,3)), for 0 <= k <= n*(n+3)/2, n >= 1 (as an irregular triangle). - G. C. Greubel, Jul 18 2022

A024693 a(n) = s(1)*t(n) + s(2)*t(n-1) + ... + s(k)*t(n+1-k), where k = floor((n+1)/2), s = A023533, t = A014306.

Original entry on oeis.org

0, 1, 1, 0, 1, 1, 1, 2, 2, 1, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 3, 3, 2, 3, 3, 3, 3, 3, 2, 3, 3, 3, 3, 3, 2, 3, 3, 2, 3, 4, 4, 4, 4, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 3, 4, 3, 4, 4, 3, 4, 4, 4, 4, 4, 3, 4, 4, 4, 4, 5, 5, 5, 5, 5, 4, 5, 5, 5, 5, 5, 5, 5, 5, 4, 5, 5, 4, 5, 5, 4
Offset: 1

Views

Author

Keywords

Crossrefs

Programs

  • Magma
    A023533:= func< n | Binomial(Floor((6*n-1)^(1/3)) +2, 3) ne n select 0 else 1 >;
    [(&+[A023533(k)*(1-A023533(n+1-k)): k in [1..Floor((n+1)/2)]]): n in [1..100]]; // G. C. Greubel, Jul 15 2022
    
  • Mathematica
    A023533[n_]:= If[Binomial[Floor[Surd[6*n-1, 3]] +2, 3] != n, 0, 1];
    A024693[n_]:= A024693[n]= Sum[(1-A023533[n-k+2])*A023533[k], {k,Floor[(n+1)/2]}];
    Table[A024693[n], {n,0,100}] (* G. C. Greubel, Jul 15 2022 *)
  • SageMath
    def A023533(n):
        if binomial( floor( (6*n-1)^(1/3) ) +2, 3) != n: return 0
        else: return 1
    [sum(A023533(k)*(1-A023533(n-k+1)) for k in (1..((n+1)//2))) for n in (1..100)] # G. C. Greubel, Jul 15 2022

Formula

a(n) = Sum_{k=1..floor((n+1)/2)} A023533(k)*A014306(n+1-k).
a(n) = Sum_{k=1..floor((n+1)/2)} A023533(k)*(1 - A023533(n-k+1)). - G. C. Greubel, Jul 15 2022

A025075 a(n) = s(1)*t(n+1) + s(2)*t(n) + ... + s(k)*t(n-k+2), where k = floor((n+1)/2), s = A023532, t = A023533.

Original entry on oeis.org

0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 1, 0, 1, 1, 1, 0, 0, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 2, 1, 2, 2, 0, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 2, 1, 2, 2, 1, 1, 2, 2, 1, 2, 2, 2, 2, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 2, 1, 2, 2, 1, 2, 1, 2, 1, 2, 2, 2, 2, 1, 2, 1, 2, 2, 2, 1, 2, 2, 2, 2, 2, 1, 1, 1, 1
Offset: 1

Views

Author

Keywords

Crossrefs

Programs

Formula

a(n)= Sum{k=1..floor((n+1)/2)} A023532(k) * A023533(n-k+2).

A025109 a(n) = s(1)*t(n) + s(2)*t(n-1) + ... + s(k)*t(n-k+1), where k = floor(n/2), s = (F(2), F(3), F(4), ...), t = A023533.

Original entry on oeis.org

0, 0, 1, 2, 3, 0, 0, 0, 1, 2, 3, 5, 8, 13, 21, 34, 55, 0, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1598, 2586, 4184, 6770, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765, 10946, 17711, 28658, 46370, 75028, 121398, 196426, 317824, 514250
Offset: 2

Views

Author

Keywords

Crossrefs

Programs

  • Magma
    A023533:= func< n | Binomial(Floor((6*n-1)^(1/3)) +2, 3) ne n select 0 else 1 >;
    [(&+[Fibonacci(k+1)*A023533(n-k+1): k in [1..Floor(n/2)]]): n in [2..100]]; // G. C. Greubel, Jul 14 2022
    
  • Mathematica
    A023533[n_]:= If[Binomial[Floor[Surd[6*n-1, 3]] + 2, 3] != n, 0, 1];
    A025109[n_]:= A025109[n]= Sum[Fibonacci[k+1]*A023533[n+1-k], {k, Floor[n/2]}];
    Table[A025109[n], {n, 2, 100}] (* G. C. Greubel, Jul 14 2022 *)
  • SageMath
    def A023533(n):
        if binomial( floor( (6*n-1)^(1/3) ) +2, 3) != n: return 0
        else: return 1
    [sum(fibonacci(k+1)*A023533(n-k+1) for k in (1..(n//2))) for n in (2..100)] # G. C. Greubel, Jul 14 2022

Formula

a(n) = Sum_{k=1..floor(n/2)} Fibonacci(k+1)*A023533(n-k+1).

Extensions

a(36) corrected by Sean A. Irvine, Aug 07 2019
Offset corrected by G. C. Greubel, Jul 14 2022
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