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.

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A296228 Decimal expansion of the limiting ratio of terms in A296227.

Original entry on oeis.org

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

Views

Author

Clark Kimberling, Dec 10 2017

Keywords

Comments

See A296000 for a guide to related sequences and limiting ratios.

Examples

			4.3033963031...
		

Crossrefs

Programs

  • Mathematica
    mex[list_] := NestWhile[# + 1 &, 1, MemberQ[list, #] &];
    a[0] = 1; a[1] = 2; b[0] = 3;
    a[n_] := a[n] = - n + Sum[a[k]*b[n - k - 1], {k, 0, n - 1}];
    b[n_] := b[n] = mex[Flatten[Table[Join[{a[n]}, {a[i], b[i]}], {i, 0, n - 1}]]];
    Table[a[n], {n, 0, 200}]  (* A296227 *)
    Table[b[n], {n, 0, 20}]
    N[Table[a[n]/a[n - 1], {n, 1, 200, 10}], 200];
    RealDigits[Last[t], 10][[1]] (* A296228 *)

Formula

Equals lim_{n->oo} A296227(n)/A296227(n-1).

A296219 Solution of the complementary equation a(n) = a(0)*b(n-1) + a(1)*b(n-2), where a(0) = 1, a(1) = 3, b(0) = 2, and (a(n)) and (b(n)) are increasing complementary sequences.

Original entry on oeis.org

1, 3, 10, 17, 21, 25, 29, 33, 38, 45, 49, 53, 57, 61, 66, 73, 77, 82, 89, 93, 98, 105, 109, 114, 121, 125, 130, 137, 141, 145, 150, 157, 161, 165, 169, 173, 178, 185, 189, 194, 201, 205, 210, 217, 221, 226, 233, 237, 242, 249, 253, 257, 262, 269, 273, 277
Offset: 0

Views

Author

Clark Kimberling, Dec 08 2017

Keywords

Comments

The increasing complementary sequences a() and b() are uniquely determined by the titular equation and initial values. See A295862 for a guide to related sequences.

Examples

			a(0) = 1, a(1) = 3, b(0) = 2, b(1) = 4
a(2) = a(0)*b(1) + a(1)*b(0) = 10
Complement: (b(n)) = (2, 4, 5, 6, 7, 8, 9, 11, 12, 13, 14, 15, 16, 18, ...)
		

Crossrefs

Cf. A296000.

Programs

  • Mathematica
    mex[list_] := NestWhile[# + 1 &, 1, MemberQ[list, #] &];
    a[0] = 1; a[1] = 3; b[0] = 2;
    a[n_] := a[n] = a[0]*b[n - 1] + a[1]*b[n - 2];
    b[n_] := b[n] = mex[Flatten[Table[Join[{a[n]}, {a[i], b[i]}], {i, 0, n - 1}]]];
    u = Table[a[n], {n, 0, 500}];  (* A296219 *)
    Table[b[n], {n, 0, 20}]

Extensions

Conjectured g.f. removed by Alois P. Heinz, Jun 25 2018
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