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.

A274210 Decimal expansion of the reciprocal of the constant in A274195.

Original entry on oeis.org

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

Views

Author

Clark Kimberling, Jun 16 2016

Keywords

Examples

			Limiting ratio = 0.770035965712929198792214166196...
		

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, 3 k]];
    t = Table[g[n, k], {n, 0, z}, {k, 0, n}];
    w = Map[Total, t]; (*A274194*)
    u = N[w[[z]]/w[[z + 1]], 100]
    RealDigits[u][[1]] (*A274210*)

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 *)

A274193 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-1,3k) for n > 0, k > 1.

Original entry on oeis.org

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

Views

Author

Clark Kimberling, Jun 14 2016

Keywords

Examples

			First  10 rows:
1
1   1
1   1   1
1   1   1   1
1   2   1   1   1
1   2   2   1   1   1
1   2   2   2   1   1   1
1   3   3   2   2   1   1   1
1   3   4   3   2   2   1   1   1
1   4   4   4   3   2   2   1   1   1
		

Crossrefs

Cf. A274194 (row sums), A274195, A274200 (limiting reverse row), A274190, 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, 3 k]];
    t = Table[g[n, k], {n, 0, 14}, {k, 0, n}]
    TableForm[t] (* A274193 array *)
    u = Flatten[t] (* A274193 sequence *)

A274194 Row sums of the array A274193, defined by g(n,k) = 1 for n >= 0; g(n,k) = 0 if k > n; g(n,k) = g(n-1,k-1) + g(n-1,3k) for n > 0, k > 1.

Original entry on oeis.org

1, 2, 3, 4, 6, 8, 10, 14, 18, 23, 31, 40, 52, 68, 88, 114, 148, 192, 249, 323, 420, 545, 707, 919, 1191, 1547, 2009, 2606, 3386, 4396, 5707, 7413, 9623, 12496, 16228, 21069, 27363, 35531, 46139, 59920, 77806, 101043, 131215, 170392, 221283, 287355, 373168
Offset: 0

Views

Author

Clark Kimberling, Jun 14 2016

Keywords

Comments

See A274195 for the limit of a(n)/a(n-1).

Examples

			(g(9,k)) = (1,4,4,4,3,2,2,1,1,1), so that a(9) = 23.
		

Crossrefs

Programs

  • Mathematica
    z = 150; 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, 3 k]];
    t = Table[g[n, k], {n, 0, z}, {k, 0, n}]; w = Map[Total, t];
Showing 1-4 of 4 results.