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.

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A023565 Convolution of A023531 and A023533.

Original entry on oeis.org

0, 1, 0, 0, 2, 0, 0, 1, 1, 0, 1, 1, 0, 2, 0, 0, 1, 1, 0, 1, 1, 0, 2, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 0, 1, 2, 0, 1, 2, 0, 0, 0, 1, 2, 0, 1, 1, 1, 0, 0, 0, 0, 1, 3, 0, 0, 2, 0, 0, 1, 1, 0, 2, 1, 1, 0, 0, 1, 2, 0, 0, 0, 1, 1, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 1, 1, 0, 2, 0, 2
Offset: 1

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Programs

  • Magma
    A023531:= func< n | IsIntegral((Sqrt(8*n+9) - 3)/2) select 1 else 0 >;
    A023533:= func< n | Binomial(Floor((6*n-1)^(1/3)) +2, 3) ne n select 0 else 1 >;
    [(&+[A023533(k)*A023531(n+1-k): k in [1..n]]): n in [1..100]]; // G. C. Greubel, Jul 16 2022
    
  • Mathematica
    A023531[n_]:= If[IntegerQ[(Sqrt[8*n+9] -3)/2], 1, 0];
    A023533[n_]:= If[Binomial[Floor[Surd[6*n-1, 3]] +2, 3] != n, 0, 1];
    A023565[n_]:= A023565[n]= Sum[A023533[k]*A023531[n-k+1], {k,n}];
    Table[A023565[n], {n,100}] (* G. C. Greubel, Jul 16 2022 *)
  • SageMath
    @CachedFunction
    def A023531(n): return 1 if ((sqrt(8*n+9) -3)/2).is_integer()  else 0
    @CachedFunction
    def A023533(n): return 0 if binomial( floor((6*n-1)^(1/3)) +2, 3)!=n else 1
    [sum(A023533(k)*A023531(n-k+1) for k in (1..n)) for n in (1..100)] # G. C. Greubel, Jul 16 2022

Formula

a(n) = Sum_{j=1..n} A023533(j) * A023531(n-j+1). - G. C. Greubel, Jul 16 2022

A023604 Convolution of A023532 and A023533.

Original entry on oeis.org

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

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Programs

  • Magma
    A023532:= func< n | IsIntegral((Sqrt(8*n+9) - 3)/2) select 0 else 1 >;
    A023533:= func< n | Binomial(Floor((6*n-1)^(1/3)) +2, 3) ne n select 0 else 1 >;
    [(&+[A023533(k)*A023532(n+1-k): k in [1..n]]): n in [1..100]]; // G. C. Greubel, Jul 16 2022
    
  • Mathematica
    A023533[n_]:= If[Binomial[Floor[Surd[6*n-1, 3]] +2, 3] != n, 0, 1];
    A023531[n_]:= If[IntegerQ[(Sqrt[8*n+9] -3)/2], 1, 0];
    A023604[n_]:= A023604[n]= Sum[A023533[k]*(1-A023531[n-k+1]), {k,n}];
    Table[A023604[n], {n,100}] (* G. C. Greubel, Jul 16 2022 *)
  • SageMath
    def A023532(n): return 0 if ((sqrt(8*n+9) -3)/2).is_integer() else 1
    @CachedFunction
    def A023533(n): return 0 if (binomial( floor( (6*n-1)^(1/3) ) +2, 3) != n) else 1
    [sum(A023533(k)*A023532(n-k+1) for k in (1..n)) for n in (1..100)] # G. C. Greubel, Jul 16 2022

Formula

From G. C. Greubel, Jul 16 2022: (Start)
a(n) = Sum_{j=1..n} A023532(n-j+1) * A023533(j).
a(n) = Sum_{j=1..n} (1 - A023531(n-j+1)) * A023533(j). (End)

A023623 Convolution of Lucas numbers and A023533.

Original entry on oeis.org

1, 3, 4, 8, 14, 22, 36, 58, 94, 153, 249, 402, 651, 1053, 1704, 2757, 4461, 7218, 11679, 18898, 30579, 49477, 80056, 129533, 209589, 339122, 548711, 887833, 1436544, 2324377, 3760921, 6085298, 9846219
Offset: 1

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Programs

  • Magma
    A023533:= func< n | Binomial(Floor((6*n-1)^(1/3)) +2, 3) ne n select 0 else 1 >;
    [(&+[Lucas(k)*A023533(n+2-k): k in [1..n+1]]): n in [0..50]]; // G. C. Greubel, Jul 16 2022
    
  • Mathematica
    Table[Sum[LucasL[m+2-Binomial[j+3,3]], {j,0,n}], {n,0,5}, {m, Binomial[n+3,3] -1, Binomial[n+4,3] -2}]//Flatten (* G. C. Greubel, Jul 16 2022 *)
  • SageMath
    def A023623(n, k): return sum(lucas_number2(k-binomial(j+3,3),1,-1) for j in (0..n))
    flatten([[A023623(n, k) for k in (binomial(n+3,3)+1..binomial(n+4,3))] for n in (0..5)]) # G. C. Greubel, Jul 16 2022

Formula

a(n) = Sum_{j=1..n+1} LucasL(j) * A023533(n-j+1). - G. C. Greubel, Jul 16 2022

A023655 Convolution of (F(2), F(3), F(4), ...) and A023533.

Original entry on oeis.org

1, 2, 3, 6, 10, 16, 26, 42, 68, 111, 180, 291, 471, 762, 1233, 1995, 3228, 5223, 8451, 13675, 22127, 35802, 57929, 93731, 151660, 245391, 397051, 642442, 1039493, 1681935, 2721428, 4403363, 7124791
Offset: 1

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Crossrefs

Essentially the same as A023613.

Programs

  • Magma
    A023533:= func< n | Binomial(Floor((6*n-1)^(1/3)) +2, 3) ne n select 0 else 1 >;
    [(&+[Fibonacci(k+2)*A023533(n-k): k in [0..n-1]]): n in [1..50]]; // G. C. Greubel, Jul 16 2022
    
  • Mathematica
    Table[Sum[Fibonacci[m+1 -Binomial[j+3,3]], {j,0,n}], {n,0,5}, {m, Binomial[n+3,3] +1, Binomial[n+4,3]}]//Flatten (* G. C. Greubel, Jul 16 2022 *)
  • SageMath
    def A023655(n, k): return sum(fibonacci(k+1-binomial(j+3,3)) for j in (0..n))
    flatten([[A023655(n, k) for k in (binomial(n+3,3)+1..binomial(n+4,3))] for n in (0..5)]) # G. C. Greubel, Jul 16 2022

Formula

a(n) = Sum_{k=0..n-1} Fibonacci(k+2) * A023533(n-k), n >= 1. - G. C. Greubel, Jul 16 2022

A023660 Convolution of odd numbers and A023533.

Original entry on oeis.org

1, 3, 5, 8, 12, 16, 20, 24, 28, 33, 39, 45, 51, 57, 63, 69, 75, 81, 87, 94, 102, 110, 118, 126, 134, 142, 150, 158, 166, 174, 182, 190, 198, 206, 215, 225, 235, 245, 255, 265, 275, 285, 295, 305, 315, 325, 335, 345, 355, 365, 375, 385, 395, 405
Offset: 1

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Programs

  • Magma
    A023533:= func< n | Binomial(Floor((6*n-1)^(1/3)) +2, 3) ne n select 0 else 1 >;
    [(&+[(2*k+1)*A023533(n-k): k in [0..n-1]]): n in [1..80]]; // G. C. Greubel, Jul 17 2022
    
  • Mathematica
    Table[(2*k+1)*n + 6*Binomial[n+2,4], {n, 7}, {k,0,n*(n+3)/2}]//Flatten (* G. C. Greubel, Jul 17 2022 *)
  • SageMath
    def A023660(n, k): return (2*k+1)*n + 6*binomial(n+2, 4)
    flatten([[A023660(n,k) for k in (0..n*(n+3)/2)] for n in (1..7)]) # G. C. Greubel, Jul 17 2022

Formula

From G. C. Greubel, Jul 17 2022: (Start)
a(n) = Sum_{j=0..n-1} (2*j+1)*A023533(n-j).
a(n) = 2*A023543(n-1) + A056556(n).
T(n, k) = (2*k+1)*n + 6*binomial(n+2, 4), for 0 <= k <= n*(n+3)/2 and n >= 1 (as an irregular triangle). (End)

A023668 Convolution of A001950 and A023533.

Original entry on oeis.org

2, 5, 7, 12, 18, 22, 28, 33, 38, 46, 53, 61, 70, 77, 85, 93, 100, 109, 116, 126, 137, 147, 158, 168, 178, 190, 199, 210, 221, 230, 242, 252, 262, 274, 285, 299, 312, 324, 339, 350, 364, 377, 390, 404, 416, 429, 444, 455, 469, 482, 494, 509, 521
Offset: 1

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Crossrefs

Programs

  • Magma
    A023533:= func< n | Binomial(Floor((6*n-1)^(1/3)) +2, 3) ne n select 0 else 1 >;
    [(&+[Floor(k*(3+Sqrt(5))/2)*A023533(n-k+1): k in [1..n]]): n in [1..80]]; // G. C. Greubel, Jul 18 2022
    
  • Mathematica
    A023668[n_, k_]:= A023668[n, k]= Sum[Floor[(k+1 +Binomial[n+2,3] -Binomial[j+2, 3])*GoldenRatio^2], {j, n}];
    Table[A023668[n, k], {n, 7}, {k,0,n*(n+3)/2}] (* G. C. Greubel, Jul 18 2022 *)
  • SageMath
    def A023668(n, k): return sum( floor((k+1 + binomial(n+2,3) - binomial(j+2,3))*golden_ratio^2) for j in (1..n) )
    flatten([[A023668(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} A001950(j) * A023533(n-j+1).
T(n, k) = Sum_{j=1..n} A001950(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

A023671 Convolution of A023533 and A014306.

Original entry on oeis.org

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

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Programs

Formula

a(n) = Sum_{j=1..n} A023533(n-j+1)*A014306(j).
From G. C. Greubel, Jul 18 2022: (Start)
a(n) = Sum_{j=1..n} A023533(n-j+1)*(1 - A023533(j)).
a(n) = A056556(n) - A023670(n). (End)

A023672 Convolution of A023533 and primes.

Original entry on oeis.org

2, 3, 5, 9, 14, 18, 24, 30, 36, 48, 53, 65, 77, 85, 97, 111, 121, 131, 149, 163, 174, 192, 204, 220, 242, 260, 272, 294, 310, 320, 350, 364, 382, 410, 436, 453, 469, 495, 513, 543, 569, 587, 615, 647, 661, 687, 715, 739, 759, 799, 827, 855, 869
Offset: 1

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Crossrefs

Programs

  • Magma
    A023533:= func< n | Binomial(Floor((6*n-1)^(1/3)) +2, 3) ne n select 0 else 1 >;
    [(&+[NthPrime(k)*A023533(n+1-k): k in [1..n]]): n in [1..100]]; // G. C. Greubel, Jul 18 2022
    
  • Mathematica
    A023672[n_, m_]:= A023672[n, m]= Sum[Prime[(m +Binomial[n+2,3] -Binomial[j+2, 3])], {j, n}];
    Table[A023672[n, m], {n,10}, {m,Binomial[n+2,2]}]//Flatten (* G. C. Greubel, Jul 18 2022 *)
  • SageMath
    def A023672(n,k): return sum(nth_prime(k +binomial(n+2,3) -binomial(j+2,3)) for j in (1..n))
    flatten([[A023672(n,k) for k in (1..binomial(n+2,2))] for n in (1..10)]) # G. C. Greubel, Jul 18 2022

Formula

a(n) = Sum_{j=1..n} A000040(j) * A023533(n-j+1).
a(n) = Sum_{j=1..n} A000040(k + binomial(n+3, 3) - binomial(j+2, 3)), for 1 <= k <= binomial(n+2, 2), n >= 1 (as an irregular triangle). - G. C. Greubel, Jul 18 2022

A023868 a(n) = 1*t(n) + 2*t(n-1) + ... + k*t(n+1-k), where k=floor((n+1)/2) and t is A023533.

Original entry on oeis.org

1, 0, 0, 1, 2, 3, 4, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 17, 19, 21, 23, 25, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 30, 32
Offset: 1

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Author

Keywords

Crossrefs

Cf. A023533.

Programs

  • Magma
    A023533:= func< n | Binomial(Floor((6*n-1)^(1/3)) +2, 3) ne n select 0 else 1 >;
    [(&+[k*A023533(n+1-k): k in [1..Floor((n+1)/2)]]): n in [1..100]]; // G. C. Greubel, Jul 18 2022
    
  • Mathematica
    A023533[n_]:= A023533[n]= If[Binomial[Floor[Surd[6*n-1,3]] +2, 3]!= n,0,1];
    A023868[n_]:= A023868[n]= Sum[j*A023533[n-j+1], {j, Floor[(n+1)/2]}];
    Table[A023868[n], {n, 100}] (* G. C. Greubel, Jul 21 2022 *)
  • SageMath
    def A023533(n): return 0 if (binomial(floor((6*n-1)^(1/3)) +2, 3)!= n) else 1
    def A023868(n): return sum(j*A023533(n-j+1) for j in (1..((n+1)//2)))
    [A023868(n) for n in (1..100)] # G. C. Greubel, Jul 21 2022

Formula

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

Extensions

Title simplified by Sean A. Irvine, Jun 12 2019

A024375 a(n) = s(1)*t(n) + s(2)*t(n-1) + ... + s(k)*t(n+1-k), where k = floor((n+1)/2), s = A023532, t = A023533.

Original entry on oeis.org

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

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