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 1-4 of 4 results.

A274192 Decimal expansion of limiting ratio described in Comments.

Original entry on oeis.org

1, 4, 8, 2, 1, 4, 6, 2, 2, 1, 0, 4, 5, 7, 9, 6, 4, 7, 3, 9, 5, 1, 0, 9, 4, 5, 0, 5, 0, 8, 9, 2, 9, 2, 1, 8, 8, 1, 0, 0, 7, 2, 2, 0, 9, 9, 2, 0, 0, 8, 2, 7, 9, 6, 3, 7, 8, 9, 8, 7, 8, 3, 7, 8, 8, 6, 2, 3, 2, 4, 8, 7, 2, 9, 2, 5, 0, 1, 6, 9, 3, 4, 8, 5, 8, 6
Offset: 1

Views

Author

Clark Kimberling, Jun 13 2016

Keywords

Comments

As in A274190, define g(n,k) = 1 for n >= 0; g(n,k) = 0 if k > n; g(n,k) = g(n-1,k-1) + g(n-1,2k) for n > 0, k > 1. The sum of numbers in the n-th row of the array {g(n,k)} is given by A274184; viz., this sum is also the number of numbers in the n-th row of the array in A274183. In other words, if we put h(0) = (0) and for n > 0 define h(n) inductively as the concatenation of h(n-1) and the numbers k/2 as k ranges through the even numbers k in h(n-1), and then let H(n) be the number of numbers in h(n), then H(n)/H(n-1) approaches 1.48214622...
This constant appears on p. 439 of Tangora's paper cited in Links.

Examples

			Limiting ratio = 1.48214622104579647395109450508929...
		

Crossrefs

Cf. A274190, A274184, A274195, A274198, A274209 (reciprocal).

Programs

  • Mathematica
    z = 1500; g[n_, 0] = g[n, 0] = 1;
    g[n_, k_] := g[n, k] = If[k > n, 0, g[n - 1, k - 1] + g[n - 1, 2 k]];
    t = Table[g[n, k], {n, 0, z}, {k, 0, n}];
    w = Map[Total, t];   (* A274184 *)
    u = N[w[[z]]/w[[z - 1]], 100]
    RealDigits[u][[1]] (* A274192 *)

A274190 Triangular array read by rows: g(n,k) = 1 for n >= 0; g(n,k) = 0 if k > n; g(n,k) = g(n-1,k-1) + g(n-1,2k) for n > 0, k > 1.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 2, 1, 1, 1, 3, 3, 2, 1, 1, 1, 4, 4, 3, 2, 1, 1, 1, 5, 6, 5, 3, 2, 1, 1, 1, 7, 8, 7, 5, 3, 2, 1, 1, 1, 9, 12, 10, 8, 5, 3, 2, 1, 1, 1, 13, 17, 15, 11, 8, 5, 3, 2, 1, 1, 1, 18, 24, 22, 17, 12, 8, 5, 3, 2, 1, 1, 1, 25, 35, 32
Offset: 0

Views

Author

Clark Kimberling, Jun 13 2016

Keywords

Examples

			First  10 rows:
1
1   1
1   1   1
1   2   1   1
1   2   2   1   1
1   3   3   2   1   1
1   4   4   3   2   1   1
1   5   6   5   3   2   1   1
1   7   8   7   5   3   2   1   1
1   9   12  10  8   5   3   2   1
		

Crossrefs

Cf. A274184 (row sums), A274192, A274199 (limiting reverse row), A274193, A274196.

Programs

  • Mathematica
    g[n_, 0] = g[n, 0] = 1;
    g[n_, k_] := g[n, k] = If[k > n, 0, g[n - 1, k - 1] + g[n - 1, 2 k]];
    t = Table[g[n, k], {n, 0, 14}, {k, 0, n}]
    TableForm[t] (* A274190 array *)
    u = Flatten[t] (* A274190 sequence *)

A274183 Irregular triangular array having n-th row g(n) defined in Comments.

Original entry on oeis.org

0, 1, 0, 2, 1, 0, 3, 2, 1, 1, 0, 4, 3, 2, 2, 1, 1, 0, 5, 4, 3, 3, 2, 2, 1, 2, 1, 1, 0, 6, 5, 4, 4, 3, 3, 2, 3, 2, 2, 1, 2, 1, 1, 1, 0, 7, 6, 5, 5, 4, 4, 3, 4, 3, 3, 2, 3, 2, 2, 2, 1, 3, 2, 2, 1, 1, 1, 1, 0, 8, 7, 6, 6, 5, 5, 4, 5, 4, 4, 3, 4, 3, 3, 3, 2, 4
Offset: 0

Views

Author

Clark Kimberling, Jun 13 2016

Keywords

Comments

Let g(0) = (0) and for n > 0, define g(n) inductively as the concatenation of g(n-1) and the numbers k/2 as k ranges through the even numbers k in g(n-1). Every nonnegative integer appears infinitely many times. For the limiting ratio of lengths of consecutive rows, see A274192.

Examples

			First six rows:
0
1   0
2   1   0
3   2   1   1   0
4   3   2   2   1   1   0
5   4   3   3   2   2   1   2   1   1   0
		

Crossrefs

Cf. A274184 (row lengths), A274192, A274185.

Programs

  • Mathematica
    g[0] = {0}; z = 14; g[n_] := g[n] = Join[g[n - 1] + 1, (1/2) Select[g[n - 1], IntegerQ[#/2] &]]; Flatten[Table[g[n], {n, 0, z}]]

A274209 Decimal expansion of the reciprocal of the constant in A274192; see Comments.

Original entry on oeis.org

6, 7, 4, 6, 9, 7, 2, 6, 3, 8, 7, 3, 4, 6, 8, 5, 5, 7, 2, 7, 6, 8, 0, 8, 6, 2, 9, 7, 5, 4, 9, 5, 0, 1, 5, 2, 7, 5, 4, 3, 1, 2, 9, 5, 6, 3, 0, 9, 6, 5, 1, 7, 0, 3, 9, 5, 5, 2, 2, 1, 9, 2, 8, 8, 1, 5, 1, 6, 2, 9, 1, 9, 3, 7, 9, 7, 5, 3, 2, 6, 7, 7, 6, 2, 7, 7
Offset: 0

Views

Author

Clark Kimberling, Jun 16 2016

Keywords

Comments

As in A274190, define g(n,k) = 1 for n >= 0; g(n,k) = 0 if k > n; g(n,k) = g(n-1,k-1) + g(n-1,2k) for n > 0, k > 1. The sum of numbers in the n-th row of the array {g(n,k)} is given by A274184; viz., this sum is also the number of numbers in the n-th row of the array in A274183. In other words, if we put h(0) = (0) and for n > 0 define h(n) inductively as the concatenation of h(n-1) and the numbers k/2 as k ranges through the even numbers k in h(n-1), and then let H(n) be the number of numbers in h(n), then H(n)/H(n+1) approaches 0.67469726387...
This constant appears on p. 439 of Tangora's paper cited in Links.

Examples

			Limiting ratio = 0.6746972638734685572768086297549501...
		

Crossrefs

Programs

  • Mathematica
    z = 1600; g[n_, 0] = g[n, 0] = 1;
    g[n_, k_] := g[n, k] = If[k > n, 0, g[n - 1, k - 1] + g[n - 1, 2 k]];
    t = Table[g[n, k], {n, 0, z}, {k, 0, n}];
    w = Map[Total, t]; (*A274184*)
    u = N[w[[z]]/w[[z + 1]], 100]
    d = RealDigits[u][[1]] (*A274209*)
Showing 1-4 of 4 results.