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 1-6 of 6 results.

A227017 Floor(M(g(n-1)+1,..,g(n))), where M = harmonic mean and g(n) = n(3n-1)/2 = A000326(n).

Original entry on oeis.org

1, 3, 8, 17, 28, 43, 60, 81, 104, 131, 160, 193, 228, 267, 308, 353, 400, 451, 504, 561, 620, 683, 748, 817, 888, 963, 1040, 1121, 1204, 1291, 1380, 1473, 1568, 1667, 1768, 1873, 1980, 2091, 2204, 2321, 2440, 2563, 2688, 2817, 2948, 3083, 3220, 3361, 3504
Offset: 1

Views

Author

Clark Kimberling, Jul 01 2013

Keywords

Comments

Also a(n) = floor(G(g(n-1)+1,g(n))), where G = geometric mean. See A227012.

Examples

			a(1) = floor(1/(1/1)); a(2) = floor(4/(1/2 + 1/3 + 1/4 + 1/5)) = 3.
		

Crossrefs

Cf. A227012.

Programs

  • Mathematica
    z = 100; f[x_] := f[x] = 1/x; g[n_] := g[n] = n (3 n - 1)/2; s[n_] := s[n] = Sum[f[k], {k, g[n - 1] + 1, g[n]}]; v[n_] := v[n] = (g[n] - g[n - 1])/s[n]; Table[g[n], {n, 1, z}]; Table[Floor[v[n]], {n, 1, z}]

Formula

a(n) = (1/4)*(1 - (-1)^n + 4*n + 6*n^2) (conjectured).
a(n) = 2*a(n-1) - 2*a(n-3) + a(n-4) for n > 1 (conjectured).
G.f.: (-1 - x - 2*x^2 - 3*x^3 + x^4)/((-1 + x)^3 (1 + x)). (conjectured)

A227013 a(n) = floor(M(g(n-1)+1,..,g(n))), where M is the harmonic mean and g(n) = n^4.

Original entry on oeis.org

1, 6, 40, 152, 413, 920, 1792, 3173, 5232, 8160, 12173, 17512, 24440, 33245, 44240, 57760, 74165, 93840, 117192, 144653, 176680, 213752, 256373, 305072, 360400, 422933, 493272, 572040, 659885, 757480, 865520, 984725, 1115840, 1259632, 1416893, 1588440, 1775112
Offset: 1

Views

Author

Clark Kimberling, Jul 01 2013

Keywords

Comments

See A227012.

Examples

			a(1) = floor(1/(1/1)) = 1.
a(2) = floor(15/(1/2 + 1/3 + ... + 1/16)) = 6.
		

Crossrefs

Cf. A227012.

Programs

  • Mathematica
    z = 30; f[x_] := f[x] = 1/x; g[n_] := g[n] = n^4; s[n_] := s[n] = Sum[f[k], {k, g[n - 1] + 1, g[n]}]; v[n_] := v[n] = (g[n] - g[n - 1])/s[n]; Table[Floor[v[n]], {n, 1, z}]

Formula

a(n) = 47/9 + 14*n + (41*n^2)/3 + 6*n^3 + n^4 - (2/9)Cos(2*n*pi/3) (conjectured).
a(n) = 4*a(n-1) - 6*a(n-2) + 5*a(n-3) - 5*a(n-4) + 6*a(n-5) - 4*a(n-6) + a(n-7) for n > 2 (conjectured).
G.f.: (-1 - 2*x - 22*x^2 - 23*x^3 - 20*x^4 - 4*x^5 + 2*x^6 - 3*x^7 + x^8)/((-1 + x)^5 (1 + x + x^2)) (conjectured).

Extensions

Extended by Ray Chandler, Jul 15 2015

A227016 Floor(M(g(n-1)+1,..,g(n))), where M = harmonic mean and g(n) = n(n + 1)(n + 2)/6.

Original entry on oeis.org

1, 2, 7, 14, 27, 45, 69, 101, 141, 191, 252, 323, 408, 506, 618, 746, 890, 1052, 1233, 1432, 1653, 1895, 2159, 2447, 2759, 3097, 3462, 3853, 4274, 4724, 5204, 5716, 6260, 6838, 7451, 8098, 8783, 9505, 10265, 11065, 11905, 12787, 13712, 14679, 15692, 16750
Offset: 1

Views

Author

Clark Kimberling, Jul 01 2013

Keywords

Comments

See A227012.

Examples

			a(1) = floor(1/(1/1)) = 1; a(2) = floor(3/(1/2 + 1/3 + 1/4)) = 2; a(3) = floor(6/(1/5 + 1/6 + ... + 1/10)) = 7.
		

Crossrefs

Programs

  • Mathematica
    z = 200; f[x_] := f[x] = 1/x; g[n_] := g[n] = n (n + 1) (n + 2)/6; s[n_] := s[n] = Sum[f[k], {k, g[n - 1] + 1, g[n]}]; v[n_] := v[n] = (g[n] - g[n - 1])/s[n]; Table[g[n], {n, 1, z}];
    Table[Floor[v[n]], {n, 1, z}]

Formula

a(n) + 3*a(n-1) - 3*a(n-2) + a(n-3) + a(n-8) - 3*a(n-9) + 3*a(n-10) - a(n-11) for n > 1 (conjectured).
G.f.: (1 - x + 4*x^2 - 2*x^3 + 4*x^4 - x^5 + x^6 + 2*x^7 - x^8 + 3*x^9 - 3*x^10 + x^11)/((x - 1)^4 (1+x) (1+x^2) (1+x^4)) (conjectured). (G.f. found by Peter J. C. Moses, Jul 01 2013)

A227014 a(n) = floor(M(g(n-1)+1,..,g(n))), where M = harmonic mean and g(n) = n^5.

Original entry on oeis.org

1, 10, 104, 543, 1883, 5102, 11717, 23906, 44626, 77735, 128110, 201769, 305989, 449428, 642243, 896212, 1224852, 1643541, 2169636, 2822595, 3624095, 4598154, 5771249, 7172438, 8833478, 10788947, 13076362, 15736301, 18812521, 22352080
Offset: 1

Views

Author

Clark Kimberling, Jul 01 2013

Keywords

Comments

See A227012. It is conjectured that A227014 is a linear recurrence sequence with signature (5,-10,10,-5,1,...Z...,1,-5,-10,-10,-1,0,0), where ...Z... represents a string of 138 zeros; has been confirmed for a(1), a(2),..., a(150000).

Examples

			a(1) = floor(1/(1/1)) = 1.
a(2) = floor(31/(1/2 + 1/3 + ... + 1/32)) = 10.
		

Crossrefs

Programs

  • Mathematica
    Clear[g]; g[n_] := N[n^5, 100]; a = {1}; Do[AppendTo[a, Floor[(#2 - #1 + 1)/(HarmonicNumber[#2]-HarmonicNumber[#1 - 1])] &[g[k - 1] + 1, g[k]]], {k, 2, 200}]; a (* Peter J. C. Moses, Jul 05 2012 *)
    (* confirm generating function *)
    p = {1, -4, 5, 9, 54, 117, 117, 122, 118, 122, 118, 122, 118, 122,
       118, 122, 118, 122, 118, 122, 118, 122, 118, 122, 118, 122, 118,
       122, 118, 122, 118, 122, 118, 122, 118, 122, 118, 122, 118, 122,
       118, 122, 118, 122, 118, 122, 118, 122, 118, 122, 118, 122, 118,
       122, 118, 122, 118, 122, 118, 122, 118, 122, 118, 122, 118, 122,
       119, 117, 129, 107, 134, 106, 134, 106, 134, 106, 134, 106, 134,
       106, 134, 106, 134, 107, 129, 117, 119, 122, 118, 122, 118, 122,
       118, 122, 118, 122, 118, 122, 118, 122, 118, 122, 118, 122, 118,
       122, 118, 122, 118, 122, 118, 122, 118, 122, 118, 122, 118, 122,
       118, 122, 118, 122, 118, 122, 118, 122, 118, 122, 118, 122, 118,
       122, 118, 122, 118, 122, 118, 122, 118, 122, 118, 122, 118, 122,
       117, 126, 113, 113, 64, 5, 1};
    q = {0, 0, 1, -5, 10, -10, 5, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 5, -10, 10, -5,
        1}; gf = Fold[x #1 + #2 &, 0, p]/Fold[x #1 + #2 &, 0, q]; CoefficientList[Series[Factor[gf], {x, 0, 100}], x] (* Peter J. C. Moses, Jul 08 2012 *)

A227015 a(n) = floor(M(g(n-1)+1, ..., g(n))), where M = harmonic mean and g(n) = n^3 + n^2 + n + 1.

Original entry on oeis.org

2, 8, 26, 60, 117, 203, 324, 487, 696, 958, 1279, 1666, 2123, 2657, 3274, 3981, 4782, 5684, 6693, 7816, 9057, 10423, 11920, 13555, 15332, 17258, 19339, 21582, 23991, 26573, 29334, 32281, 35418, 38752, 42289, 46036, 49997, 54179, 58588, 63231, 68112, 73238
Offset: 1

Views

Author

Clark Kimberling, Jul 01 2013

Keywords

Comments

See A227012.

Crossrefs

Programs

  • Mathematica
    z = 100; f[x_] := f[x] = 1/x; g[n_] := g[n] = n^3 + n^2 + n + 1; s[n_] := s[n] = Sum[f[k], {k, g[n - 1] + 1, g[n]}]; v[n_] := v[n] = (g[n] - g[n - 1])/s[n]; Table[g[n], {n, 1, z}];
    Table[Floor[v[n]], {n, 1, z}]

Formula

a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) + a(n-4) - 3*a(n-5) + 3*a(n-6) - a(n-7) for n > 2 (conjectured).
G.f.: x*(2 + 2*x + 8*x^2 + 4*x^3 + 5*x^4 + 4*x^5 - 2*x^6 + 3*x^7 - 3*x^8 + x^9)/((x - 1)^4*(1 + x + x^2 + x^3)) (conjectured).
From Franck Maminirina Ramaharo, Apr 16 2018: (Start)
a(n) = (1/2)*((-1)^(n - 1)! + 2*n^3 - n^2 + n + 3 + 2*floor(max(0, n - 4)/4)) (conjectured).
E.g.f.: (1/24)*exp(-x)*(exp(x)*(6*sin(x) + 6*cos(x) + 4*x^3 - 24) + exp(2*x)*(24*x^3 + 60*x^2 + 30*x + 15) + 3) (conjectured).
(End)

A227018 a(n) = floor(M(g(n-1)+1,..,g(n))), where M = harmonic mean and g(n) = n*(n + 1)*(n + 2)*(n + 3)/24.

Original entry on oeis.org

1, 3, 9, 24, 51, 95, 164, 266, 407, 598, 850, 1174, 1582, 2087, 2706, 3452, 4342, 5395, 6628, 8060, 9714, 11609, 13768, 16215, 18975, 22072, 25534, 29388, 33662, 38387, 43591, 49307, 55568, 62407, 69858, 77957, 86740, 96245, 106511, 117577, 129482, 142270
Offset: 1

Views

Author

Clark Kimberling, Jul 06 2013

Keywords

Comments

See A227012.

Examples

			a(1) = [1/(1/1)] = 1;
a(2) = [4/(1/2 + 1/3 + 1/4 + 1/5)] = 3;
a(3) = [10/(1/6 + 1/7 + ... + 1/15)] = 9.
		

Crossrefs

Programs

  • Mathematica
    Clear[g]; g[n_] := N[Binomial[n + # - 1, #] &[4], 100]; a = {1}; Do[
    AppendTo[a, Floor[(#2 - #1 + 1)/(HarmonicNumber[#2] - HarmonicNumber[#1 - 1])] &[g[k - 1] + 1, g[k]]], {k, 2, 100}]; a

Formula

Conjectured g.f.: (-1 + x - 3 x^2 - 2 x^3 + 2 x^4 - 2 x^5 - 3 x^6 + 2 x^8 - 5 x^9 - x^12 - x^13 - 4 x^14 + 4 x^15 - 4 x^16 - 2 x^17 + 2 x^18 - 2 x^19 - 4 x^20 + 4 x^21 - 4 x^22 - x^23 - x^24 + x^25 - 4 x^26 + x^27 - x^28 - 3 x^29 + 3 x^30 - 5 x^31 - x^34 - 2 x^35 + x^36 - 3 x^37 + 2 x^38 + 2 x^39 - 2 x^40 - 3 x^41 + 6 x^42 - 3 x^43 - 3 x^44 + 6 x^45 - 4 x^46 + x^47)/((-1 + x)^5 (1 + x) (1 + x^2) (1 - x + x^2) (1 + x + x^2) (1 - x^2 + x^4) (1 - x^3 + x^6) (1 + x^3 + x^6) (1 - x^6 + x^12)).
Showing 1-6 of 6 results.