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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A093611 Numerators of convergents to 3/(1 + sqrt(10)).

Original entry on oeis.org

0, 1, 3, 4, 7, 18, 25, 43, 111, 154, 265, 684, 949, 1633, 4215, 5848, 10063, 25974, 36037, 62011, 160059, 222070, 382129, 986328, 1368457, 2354785, 6078027, 8432812, 14510839, 37454490, 51965329, 89419819, 230804967, 320224786
Offset: 1

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Author

Gary W. Adamson, Apr 04 2004

Keywords

Comments

The partial quotient terms [1 2 1 1 2 1 1 2 1...] are palindromic. The matrix generator for convergents to barover[1 2 1] = [2 3 / 3 4]^n = M^n and is Hermitian (upper right term = lower left). Therefore in any pair of convergents M^n, upper right term = lower left. Example: M^3 = [80 111 / 111 541], where 111 = a(9). Consequently a(3n) = A093612(3n-1), where A093612 = denominators of barover[1 2 1].
Denominators give same sequence shifted one place left.

Examples

			a(5) = 13 = 2*5 + 3.
		

Programs

  • Mathematica
    xx = ContinuedFraction[3/(1 + Sqrt[10]), 70]; Table[ Numerator[ FromContinuedFraction[ Take[xx, n]]], {n, 34}] (* Robert G. Wilson v, Apr 08 2004 *)
    LinearRecurrence[{0,0,6,0,0,1},{0,1,3,4,7,18,25},40] (* Harvey P. Dale, Nov 26 2021 *)

Formula

Partial quotients are [1 2 1 1 2 1...] indicating the operation below a term q. The numerator under q = n = q(n-1) + (n-2), a(1) = 1, a(2) = 2, a(3) = 3 and so on.
G.f.: x(1+3x+4x^2+x^3+x^5)/(1-6x^3-x^6). - Paul Barry, Apr 12 2010

Extensions

Corrected and extended by Robert G. Wilson v, Apr 08 2004
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