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.

A022940 a(n) = a(n-1) + b(n-2) for n >= 3, a( ) increasing, given a(1) = 1, a(2) = 3; where b( ) is complement of a( ).

Original entry on oeis.org

1, 3, 5, 9, 15, 22, 30, 40, 51, 63, 76, 90, 106, 123, 141, 160, 180, 201, 224, 248, 273, 299, 326, 354, 383, 414, 446, 479, 513, 548, 584, 621, 659, 698, 739, 781, 824, 868, 913, 959, 1006, 1054, 1103, 1153, 1205, 1258, 1312, 1367, 1423, 1480
Offset: 1

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Author

Keywords

Comments

From Clark Kimberling, Oct 30 2017: (Start)
The complementary sequences a() and b() are uniquely determined by the titular equation and initial values. The initial values of each sequence in the following guide are a(0) = 1, a(2) = 3, b(0) = 2, b(1) = 4:
here: a(n) = a(n-1) + b(n-2) [with a different offset]
A294397: a(n) = a(n-1) + b(n-2) + 1;
A294398: a(n) = a(n-1) + b(n-2) + 2;
A294399: a(n) = a(n-1) + b(n-2) + 3;
A294400: a(n) = a(n-1) + b(n-2) + n;
A294401: a(n) = a(n-1) + b(n-2) + 2*n.
(End)

Examples

			a(1) = 1, a(2) = 3, b(1) = 2, b(2) = 4, so that a(3) = a(2) + a(1) + b(2) = 5.
Complement: {b(n)} = {2, 4, 6, 7, 8, 10, 11, 12, 13, 14, 16, ...}
		

Crossrefs

Cf. A005228 and references therein.

Programs

  • Mathematica
    Fold[Append[#1, #1[[-1]] + Complement[Range[Max@#1 + 1], #1][[#2]]] &, {1, 3}, Range[50]] (* Ivan Neretin, Apr 04 2016 *)

A296492 Decimal expansion of limiting power-ratio for A294170; see Comments.

Original entry on oeis.org

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

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Author

Clark Kimberling, Dec 20 2017

Keywords

Comments

Suppose that A = (a(n)), for n >= 0, is a sequence, and g is a real number such that a(n)/a(n-1) -> g. The ratio-sum for A is |a(1)/a(0) - g| + |a(2)/a(1) - g| + ..., assuming that this series converges. For A = A294170, we have g = (1 + sqrt(5))/2, the golden ratio (A001622). See the guide at A296469 for related sequences.

Examples

			limiting power-ratio = 11.22071294787201913135639932120744822352...
		

Crossrefs

Programs

  • Mathematica
    a[0] = 1; a[1] = 2; b[0] = 3; b[1] = 4; b[2] = 5;
    a[n_] := a[n] = a[n - 1] + a[n - 2] + b[n] + 2 n;
    j = 1; While[j < 16, k = a[j] - j - 1;
    While[k < a[j + 1] - j + 1, b[k] = j + k + 2; k++]; j++];
    u = Table[a[n], {n, 0, k}];  (* A294170 *)
    z = 2000; g = GoldenRatio; h = Table[N[a[n]/g^n, z], {n, 0, z}];
    StringJoin[StringTake[ToString[h[[z]]], 41], "..."]
    Take[RealDigits[Last[h], 10][[1]], 120]   (* A296492 *)

A294382 Solution of the complementary equation a(n) = a(n-1)*b(n-2) - 1, where a(0) = 1, a(1) = 3, b(0) = 2, b(1) = 4.

Original entry on oeis.org

1, 3, 5, 19, 113, 790, 6319, 56870, 568699, 6255688, 75068255, 975887314, 13662422395
Offset: 0

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Author

Clark Kimberling, Oct 29 2017

Keywords

Comments

The complementary sequences a() and b() are uniquely determined by the titular equation and initial values. See A294381 for a guide to related sequences.

Examples

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

Crossrefs

Programs

  • Mathematica
    mex := First[Complement[Range[1, Max[#1] + 1], #1]] &;
    a[0] = 1; a[1] = 3; b[0] = 2; b[1] = 4;
    a[n_] := a[n] = a[n - 1]*b[n - 2] - 1;
    b[n_] := b[n] = mex[Flatten[Table[Join[{a[n]}, {a[i], b[i]}], {i, 0, n - 1}]]];
    Table[a[n], {n, 0, 40}]  (* A294382 *)
    Table[b[n], {n, 0, 10}]

A294383 Solution of the complementary equation a(n) = a(n-1)*b(n-2) + 1, where a(0) = 1, a(1) = 3, b(0) = 2, b(1) = 4.

Original entry on oeis.org

1, 3, 7, 29, 146, 877, 7017, 63154, 631541, 6946952, 83363425, 1083724526, 15172143365
Offset: 0

Views

Author

Clark Kimberling, Oct 29 2017

Keywords

Comments

The complementary sequences a() and b() are uniquely determined by the titular equation and initial values. See A294381 for a guide to related sequences.

Examples

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

Crossrefs

Programs

  • Mathematica
    mex := First[Complement[Range[1, Max[#1] + 1], #1]] &;
    a[0] = 1; a[1] = 3; b[0] = 2; b[1] = 4;
    a[n_] := a[n] = a[n - 1]*b[n - 2] + 1;
    b[n_] := b[n] = mex[Flatten[Table[Join[{a[n]}, {a[i], b[i]}], {i, 0, n - 1}]]];
    Table[a[n], {n, 0, 40}]  (* A294383 *)
    Table[b[n], {n, 0, 10}]

A294384 Solution of the complementary equation a(n) = a(n-1)*b(n-2) - n, where a(0) = 1, a(1) = 3, b(0) = 2, b(1) = 4.

Original entry on oeis.org

1, 3, 4, 13, 61, 361, 2521, 20161, 181441, 1814401, 19958401, 239500801, 3353011202, 50295168017
Offset: 0

Views

Author

Clark Kimberling, Oct 29 2017

Keywords

Comments

The complementary sequences a() and b() are uniquely determined by the titular equation and initial values. See A294381 for a guide to related sequences.

Examples

			a(0) = 1, a(1) = 3, b(0) = 2, b(1) = 4, so that
a(2)  = a(1)*b(0) - 2 = 4
Complement: (b(n)) = (2, 5, 6, 7, 8, 9, 10, 12, 14, 15, 16, ...)
		

Crossrefs

Programs

  • Mathematica
    mex := First[Complement[Range[1, Max[#1] + 1], #1]] &;
    a[0] = 1; a[1] = 3; b[0] = 2; b[1] = 4;
    a[n_] := a[n] = a[n - 1]*b[n - 2] - n;
    b[n_] := b[n] = mex[Flatten[Table[Join[{a[n]}, {a[i], b[i]}], {i, 0, n - 1}]]];
    Table[a[n], {n, 0, 40}]  (* A294384 *)
    Table[b[n], {n, 0, 10}]

A294385 Solution of the complementary equation a(n) = a(n-1)*b(n-2) + n, where a(0) = 1, a(1) = 3, b(0) = 2, b(1) = 4.

Original entry on oeis.org

1, 3, 8, 35, 179, 1079, 7559, 68038, 680388, 7484277, 89811334, 1167547353, 16345662954
Offset: 0

Views

Author

Clark Kimberling, Oct 29 2017

Keywords

Comments

The complementary sequences a() and b() are uniquely determined by the titular equation and initial values. See A294381 for a guide to related sequences.

Examples

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

Crossrefs

Programs

  • Mathematica
    mex := First[Complement[Range[1, Max[#1] + 1], #1]] &;
    a[0] = 1; a[1] = 3; b[0] = 2; b[1] = 4;
    a[n_] := a[n] = a[n - 1]*b[n - 2] + n;
    b[n_] := b[n] = mex[Flatten[Table[Join[{a[n]}, {a[i], b[i]}], {i, 0, n - 1}]]];
    Table[a[n], {n, 0, 40}]  (* A294385 *)
    Table[b[n], {n, 0, 10}]
Showing 1-6 of 6 results.