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.

A346050 G.f. A(x) satisfies: A(x) = x + x^2 + x^3 * A(x/(1 - x)) / (1 - x).

Original entry on oeis.org

0, 1, 1, 0, 1, 3, 6, 11, 23, 60, 179, 553, 1716, 5415, 17801, 61956, 228391, 882309, 3530322, 14531621, 61454091, 267479778, 1200680113, 5561767211, 26553471186, 130366882251, 656668581417, 3387887246292, 17886582294921, 96603394562849, 533645344137390, 3014295344076655
Offset: 0

Views

Author

Ilya Gutkovskiy, Jul 02 2021

Keywords

Crossrefs

Programs

  • Mathematica
    nmax = 31; A[] = 0; Do[A[x] = x + x^2 + x^3 A[x/(1 - x)]/(1 - x) + O[x]^(nmax + 1) // Normal, nmax + 1]; CoefficientList[A[x], x]
    a[0] = 0; a[1] = a[2] = 1; a[n_] := a[n] = Sum[Binomial[n - 3, k] a[k], {k, 0, n - 3}]; Table[a[n], {n, 0, 31}]
  • SageMath
    @CachedFunction
    def a(n): # a = A346050
        if (n<3): return (0,1,1)[n]
        else: return sum(binomial(n-3,k)*a(k) for k in range(n-2))
    [a(n) for n in range(51)] # G. C. Greubel, Nov 28 2022

Formula

a(0) = 0, a(1) = a(2) = 1; a(n) = Sum_{k=0..n-3} binomial(n-3,k) * a(k).

A346051 G.f. A(x) satisfies: A(x) = 1 + x^2 + x^3 * A(x/(1 - x)) / (1 - x).

Original entry on oeis.org

1, 0, 1, 1, 1, 2, 5, 12, 28, 68, 181, 531, 1671, 5491, 18627, 65299, 237880, 903907, 3580619, 14729777, 62639952, 274442521, 1236730244, 5729809348, 27292248240, 133614280479, 671803041553, 3464970976743, 18309428363425, 99010800275743, 547462187824465, 3093329527120022
Offset: 0

Views

Author

Ilya Gutkovskiy, Jul 02 2021

Keywords

Crossrefs

Programs

  • Magma
    function a(n)
      if n lt 3 then return (1+(-1)^n)/2;
      else return (&+[Binomial(n-3,j)*a(j): j in [0..n-3]]);
      end if; return a;
    end function;
    [a(n): n in [0..35]]; // G. C. Greubel, Nov 30 2022
    
  • Mathematica
    nmax = 31; A[] = 0; Do[A[x] = 1 + x^2 + x^3 A[x/(1 - x)]/(1 - x) + O[x]^(nmax + 1) // Normal, nmax + 1]; CoefficientList[A[x], x]
    a[0] = 1; a[1] = 0; a[2] = 1; a[n_] := a[n] = Sum[Binomial[n - 3, k] a[k], {k, 0, n - 3}]; Table[a[n], {n, 0, 31}]
  • SageMath
    @CachedFunction
    def a(n): # a = A346051
        if (n<3): return (1, 0, 1)[n]
        else: return sum(binomial(n-3, k)*a(k) for k in range(n-2))
    [a(n) for n in range(51)] # G. C. Greubel, Nov 30 2022

Formula

a(0) = 1, a(1) = 0, a(2) = 1; a(n) = Sum_{k=0..n-3} binomial(n-3,k) * a(k).

A346052 G.f. A(x) satisfies: A(x) = 1 + x + x^3 * A(x/(1 - x)) / (1 - x).

Original entry on oeis.org

1, 1, 0, 1, 2, 3, 5, 11, 29, 80, 222, 630, 1881, 6004, 20420, 72979, 270659, 1035590, 4087205, 16675630, 70440641, 307933393, 1390117953, 6462787357, 30871458702, 151298796000, 760250325004, 3915477534861, 20662363081756, 111662169790416, 617482470676567, 3490973387652861
Offset: 0

Views

Author

Ilya Gutkovskiy, Jul 02 2021

Keywords

Crossrefs

Programs

  • Magma
    function a(n) // a = A346052
      if n lt 3 then return Floor((3-n)/2);
      else return (&+[Binomial(n-3,j)*a(j): j in [0..n-3]]);
      end if; return a;
    end function;
    [a(n): n in [0..35]]; // G. C. Greubel, Nov 30 2022
    
  • Mathematica
    nmax = 31; A[] = 0; Do[A[x] = 1 + x + x^3 A[x/(1 - x)]/(1 - x) + O[x]^(nmax + 1) // Normal, nmax + 1]; CoefficientList[A[x], x]
    a[0] = a[1] = 1; a[2] = 0; a[n_] := a[n] = Sum[Binomial[n - 3, k] a[k], {k, 0, n - 3}]; Table[a[n], {n, 0, 31}]
  • SageMath
    @CachedFunction
    def a(n): # a = A346052
        if (n<3): return (1, 1, 0)[n]
        else: return sum(binomial(n-3, k)*a(k) for k in range(n-2))
    [a(n) for n in range(51)] # G. C. Greubel, Nov 30 2022

Formula

a(0) = a(1) = 1, a(2) = 0; a(n) = Sum_{k=0..n-3} binomial(n-3,k) * a(k).

A088022 a(n) = floor(sum_{k>=0} k^n /(k!)^3); related to generalized Bell numbers.

Original entry on oeis.org

2, 1, 1, 2, 3, 6, 12, 28, 68, 176, 484, 1409, 4334, 14002, 47357, 167157, 614297, 2345730, 9290084, 38092233, 161436136, 706061825, 3182452003, 14764717643, 70429572474, 345075959701, 1734987079149, 8943648710357, 47228775626154
Offset: 0

Views

Author

Paul D. Hanna, Sep 19 2003

Keywords

Examples

			a(8) = 68 = floor(17*2.1297 + 12*1.2641 + 11*1.5428) = floor(68.3463).
		

Crossrefs

Formula

B(n) := sum_{k>=0} k^n/(k!)^3 = A000996(n)*B(0) + A000997(n)*B(1) + A000998(n)*B(2) where B(0)=2.129702548983..., B(1)=1.264181150389..., B(2)=1.542838638501...; observe that these shift 3 places left under binomial transform: A000996={1, 0, 0, 1, 1, 1, 2, 6, 17, 44, 112, 304, 918, ...}, A000997={0, 1, 0, 0, 1, 2, 3, 5, 12, 36, 110, 326, 963, ...}, A000998={0, 0, 1, 0, 0, 1, 3, 6, 11, 24, 69, 227, 753, ...}; here A000998 is offset with 5 leading terms: {0, 0, 1, 0, 0}.

A351188 G.f. A(x) satisfies: A(x) = x + x^3 * A(x/(1 + x)) / (1 + x).

Original entry on oeis.org

0, 1, 0, 0, 1, -2, 3, -3, -2, 24, -94, 280, -687, 1270, -655, -9306, 65087, -306724, 1202250, -4033365, 10855578, -15470865, -69819687, 850568716, -5679272040, 30749200898, -144912453016, 593521998765, -1956641103972, 3349999455415, 20123433921282, -295760693980981
Offset: 0

Views

Author

Ilya Gutkovskiy, Feb 04 2022

Keywords

Comments

Shifts 3 places left under inverse binomial transform.

Crossrefs

Programs

  • Mathematica
    nmax = 31; A[] = 0; Do[A[x] = x + x^3 A[x/(1 + x)]/(1 + x) + O[x]^(nmax + 1) // Normal, nmax + 1]; CoefficientList[A[x], x]
    a[0] = 0; a[1] = 1; a[2] = 0; a[n_] := a[n] = Sum[(-1)^k Binomial[n - 3, k] a[n - k - 3], {k, 0, n - 3}]; Table[a[n], {n, 0, 31}]

Formula

a(0) = 0, a(1) = 1, a(2) = 0; a(n) = Sum_{k=0..n-3} (-1)^k * binomial(n-3,k) * a(n-k-3).
Showing 1-5 of 5 results.