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.

A296434 Decimal expansion of ratio-sum for A296292; see Comments.

Original entry on oeis.org

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

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Author

Clark Kimberling, Dec 15 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 = A296292 we have g = (1 + sqrt(5))/2, the golden ratio (A001622). See A296425-A296434 for related ratio-sums and A296452-A296461 for related limiting power-ratios.

Examples

			Ratio-sum = 8.012968903095661472515541...
		

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] + n*b[n];
    j = 1; While[j < 13, k = a[j] - j - 1;
    While[k < a[j + 1] - j + 1, b[k] = j + k + 2; k++]; j++];
    Table[a[n], {n, 0, k}]; (* A296292 *)
    g = GoldenRatio; s = N[Sum[- g + a[n]/a[n - 1], {n, 1, 1000}], 200]
    Take[RealDigits[s, 10][[1]], 100]  (* A296434 *)