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.

A295755 Solution of the complementary equation a(n) = a(n-1) + a(n-3) + a(n-4) + b(n-3), where a(0) = 1, a(1) = 2, a(2) = 3, a(3) = 4, b(0) = 5, b(1) = 6, b(2) = 7, b(3) = 8, and (a(n)) and (b(n)) are increasing complementary sequences.

Original entry on oeis.org

1, 2, 3, 4, 13, 25, 40, 66, 114, 190, 308, 502, 821, 1335, 2162, 3503, 5678, 9195, 14881, 24084, 38980, 63080, 102071, 165162, 267250, 432430, 699693, 1132136, 1831848, 2964004, 4795867, 7759886, 12555774, 20315682, 32871473, 53187172, 86058669, 139245866
Offset: 0

Views

Author

Clark Kimberling, Nov 30 2017

Keywords

Comments

The increasing complementary sequences a() and b() are uniquely determined by the titular equation and initial values.
a(n)/a(n-1) -> (1 + sqrt(5))/2 = golden ratio (A001622), so that a( ) has the growth rate of the Fibonacci numbers (A000045).

Examples

			a(0) = 1, a(1) = 2, a(2) = 3, a(3) = 4, b(0) = 5, b(1) = 6, b(2) = 7, b(3) = 8, so that
b(4) = 9 (least "new number")
a(4) = a(3) + a(1) + a(0) + b(1) = 13
Complement: (b(n)) = (5, 6, 7, 8, 9, 10, 11, 12, 14, 15, ...)
		

Crossrefs

Programs

  • Mathematica
    mex := First[Complement[Range[1, Max[#1] + 1], #1]] &;
    a[0] = 1; a[1] = 2; a[2] = 3; a[3] = 4;
    b[0] = 5; b[1] = 6; b[2] = 7; b[3] = 8;
    a[n_] := a[n] = a[n - 1] + a[n - 3] + a[n - 4] + b[n - 3];
    b[n_] := b[n] = mex[Flatten[Table[Join[{a[n]}, {a[i], b[i]}], {i, 0, n - 1}]]];
    z = 36;  Table[a[n], {n, 0, z}]   (* A295755 *)
    Table[b[n], {n, 0, 20}]  (*complement *)

A295756 Solution of the complementary equation a(n) = a(n-1) + a(n-3) + a(n-4) + b(n-2), where a(0) = 1, a(1) = 2, a(2) = 3, a(3) = 4, b(0) = 5, b(1) = 6, b(2) = 7, b(3) = 8, and (a(n)) and (b(n)) are increasing complementary sequences.

Original entry on oeis.org

1, 2, 3, 4, 14, 27, 43, 71, 123, 205, 332, 541, 885, 1439, 2330, 3775, 6119, 9909, 16036, 25953, 42005, 67975, 109990, 177976, 287985, 465980, 753977, 1219970, 1973968, 3193959, 5167941, 8361915, 13529879, 21891817, 35421712, 57313546, 92735283, 150048854
Offset: 0

Views

Author

Clark Kimberling, Dec 01 2017

Keywords

Comments

The increasing complementary sequences a() and b() are uniquely determined by the titular equation and initial values.
a(n)/a(n-1) -> (1 + sqrt(5))/2 = golden ratio (A001622), so that a( ) has the growth rate of the Fibonacci numbers (A000045).

Examples

			a(0) = 1, a(1) = 2, a(2) = 3, a(3) = 4, b(0) = 5, b(1) = 6, b(2) = 7, b(3) = 8, so that
b(4) = 9 (least "new number")
a(4) = a(3) + a(1) + a(0) + b(2) = 14
Complement: (b(n)) = (5, 6, 7, 8, 9, 10, 11, 12, 13, 15, ...)
		

Crossrefs

Programs

  • Mathematica
    mex := First[Complement[Range[1, Max[#1] + 1], #1]] &;
    a[0] = 1; a[1] = 2; a[2] = 3; a[3] = 4;
    b[0] = 5; b[1] = 6; b[2] = 7; b[3] = 8;
    a[n_] := a[n] = a[n - 1] + a[n - 3] + a[n - 4] + b[n - 2];
    b[n_] := b[n] = mex[Flatten[Table[Join[{a[n]}, {a[i], b[i]}], {i, 0, n - 1}]]];
    z = 36;  Table[a[n], {n, 0, z}]   (* A295756 *)
    Table[b[n], {n, 0, 20}]  (*complement *)

A295757 Solution of the complementary equation a(n) = a(n-1) + a(n-3) + a(n-4) + b(n-1), where a(0) = 1, a(1) = 2, a(2) = 3, a(3) = 4, b(0) = 5, b(1) = 6, b(2) = 7, b(3) = 8, and (a(n)) and (b(n)) are increasing complementary sequences.

Original entry on oeis.org

1, 2, 3, 4, 15, 29, 46, 76, 132, 220, 356, 580, 949, 1543, 2498, 4047, 6560, 10623, 17191, 27822, 45030, 72870, 117910, 190790, 308720, 499531, 808263, 1307806, 2116091, 3423920, 5540025, 8963959, 14504008, 23467992, 37972016, 61440024, 99412066, 160852117
Offset: 0

Views

Author

Clark Kimberling, Dec 01 2017

Keywords

Comments

The increasing complementary sequences a() and b() are uniquely determined by the titular equation and initial values.
a(n)/a(n-1) -> (1 + sqrt(5))/2 = golden ratio (A001622), so that a( ) has the growth rate of the Fibonacci numbers (A000045).

Examples

			a(0) = 1, a(1) = 2, a(2) = 3, a(3) = 4, b(0) = 5, b(1) = 6, b(2) = 7, b(3) = 8, so that
b(4) = 9 (least "new number")
a(4) = a(3) + a(1) + a(0) + b(3) = 15
Complement: (b(n)) = (5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 16, ...)
		

Crossrefs

Programs

  • Mathematica
    mex := First[Complement[Range[1, Max[#1] + 1], #1]] &;
    a[0] = 1; a[1] = 2; a[2] = 3; a[3] = 4;
    b[0] = 5; b[1] = 6; b[2] = 7; b[3] = 8;
    a[n_] := a[n] = a[n - 1] + a[n - 3] + a[n - 4] + b[n - 1];
    b[n_] := b[n] = mex[Flatten[Table[Join[{a[n]}, {a[i], b[i]}], {i, 0, n - 1}]]];
    z = 36;  Table[a[n], {n, 0, z}]   (* A295757 *)
    Table[b[n], {n, 0, 20}]  (*complement *)
Showing 1-3 of 3 results.