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 1-3 of 3 results.

A248630 Numbers k such that A248630(k+1) = A248360(k) + 1.

Original entry on oeis.org

7, 11, 15, 18, 22, 25, 28, 31, 34, 37, 39, 42, 45, 48, 51, 53, 56, 59, 61, 64, 67, 69, 72, 75, 77, 80, 82, 85, 88, 90, 93, 95, 98, 101, 103, 106, 108, 111, 113, 116, 118, 121, 124, 126, 129, 131, 134, 136, 139, 141, 144, 146, 149, 151, 154, 156, 159, 161
Offset: 1

Views

Author

Clark Kimberling, Oct 10 2014

Keywords

Examples

			(A248630(k+1) = A248360(k)) = (2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 1, 2, 2, 2, 1, 2, 2, 1, ...), so that A248630 = (7, 11, 15, 18, ...).
		

Crossrefs

Programs

  • Mathematica
    z = 300; p[k_] := p[k] = Sum[(h^2/2^h), {h, 1, k}]
    d = N[Table[6 - p[k], {k, 1, z/5}], 12]
    f[n_] := f[n] = Select[Range[z], 6 - p[#] < 1/3^n &, 1]
    u = Flatten[Table[f[n], {n, 1, z}]]  (* A248629 *)
    d = Differences[u]
    v = Flatten[Position[d, 1]]  (* A248630 *)

A248632 Numbers k such that A248631(k+1) = A248631(k).

Original entry on oeis.org

6, 10, 14, 17, 21, 24, 27, 30, 33, 36, 39, 42, 45, 48, 51, 54, 57, 60, 63, 66, 69, 72, 75, 77, 80, 83, 86, 89, 92, 95, 97, 100, 103, 106, 109, 111, 114, 117, 120, 123, 126, 128, 131, 134, 137, 140, 142, 145, 148, 151, 154, 156, 159, 162, 165, 168, 170, 173
Offset: 1

Views

Author

Clark Kimberling, Oct 11 2014

Keywords

Examples

			(A248631(k+1) = A248631(k)) = (1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1,... ), so that A248632 = (6, 10, 14, ... ).
		

Crossrefs

Programs

  • Mathematica
    z = 200; p[k_] := p[k] = Sum[(h^2/2^h), {h, 1, k}];
    d = N[Table[6 - p[k], {k, 1, z/5}], 12];
    f[n_] := f[n] = Select[Range[z], 6 - p[#] < 1/3^n &, 1];
    u = Flatten[Table[f[n], {n, 1, z}]]; (* A248629 *)
    d = Differences[u];
    Flatten[Position[d, 1]];  (* A248630 *)

A248631 Least k such that 3/2 - sum{(h^2)/3^h, h = 1..k} < 1/2^n.

Original entry on oeis.org

3, 4, 5, 6, 7, 8, 8, 9, 10, 11, 11, 12, 13, 14, 14, 15, 16, 16, 17, 18, 19, 19, 20, 21, 21, 22, 23, 23, 24, 25, 25, 26, 27, 27, 28, 29, 29, 30, 31, 31, 32, 33, 33, 34, 35, 35, 36, 37, 37, 38, 39, 39, 40, 41, 41, 42, 43, 43, 44, 45, 45, 46, 47, 47, 48, 49, 49
Offset: 1

Views

Author

Clark Kimberling, Oct 11 2014

Keywords

Comments

This sequence provides insight into the manner of convergence of sum{(h^2)/3^h, h = 1..k} to 3/2.

Examples

			Let s(n) = 3/2 - sum{(h^2)/3^h, h = 1..n}.  Approximations follow:
n ... s(n) ...... 1/2^n
1 ... 1.16666 ... 0.500000
2 ... 0.72222 ... 0.250000
3 ... 0.38888 ... 0.125000
4 ... 0.03909 ... 0.062500
5 ... 0.08847 ... 0.031250
6 ... 0.03909 ... 0.015625
7 ... 0.01668 ... 0.007812
a(5) = 7 because s(7) < 1/32 < s(6).
		

Crossrefs

Programs

  • Mathematica
    z = 200; p[k_] := p[k] = Sum[(h^2/2^h), {h, 1, k}];
    d = N[Table[6 - p[k], {k, 1, z/5}], 12];
    f[n_] := f[n] = Select[Range[z], 6 - p[#] < 1/3^n &, 1];
    u = Flatten[Table[f[n], {n, 1, z}]]; (* A248629 *)
    d = Differences[u];
    Flatten[Position[d, 1]];  (* A248630 *)
Showing 1-3 of 3 results.