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.

A294176 Squarefree d such that the fundamental unit of Q(sqrt(d)) is larger than the fundamental unit of Q(sqrt(d)) for any smaller d.

Original entry on oeis.org

2, 3, 6, 7, 11, 14, 19, 22, 31, 43, 46, 67, 94, 127, 139, 151, 199, 211, 214, 331, 379, 454, 526, 571, 631, 739, 751, 886, 919, 991, 1291, 1366, 1699, 1726, 1999, 2011, 2311, 2326, 2566, 2671, 3019, 3259, 3691, 3931, 4174, 4846, 4951, 5119, 6211, 6379, 6406, 6451, 7606, 8254, 8779, 9619
Offset: 1

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Author

Alonso del Arte, Feb 10 2018

Keywords

Examples

			The fundamental unit of Z[sqrt(2)] is 1 + sqrt(2) = 2.414213562373...
The fundamental unit of Z[sqrt(3)] is 2 + sqrt(3) = 3.7320508..., which is larger than 2.414213562373...
Thus the sequence starts out 2, 3.
The fundamental unit of O_(Q(sqrt(5))) is 1/2 + sqrt(5)/2 = 1.618..., which is actually smaller than the previous units, so 5 is not in the sequence.
The next term in the sequence is 6, corresponding to 5 + 2 sqrt(6) = 9.8989794855663561963945681494...
		

Crossrefs

Programs

  • Mathematica
    k = 2; A294176 = {}; mx = 0; While[k < 1000, If[SquareFreeQ@ k && N[NumberFieldFundamentalUnits[Sqrt[k]], 16][[1]] > mx, mx = N[NumberFieldFundamentalUnits[Sqrt[k]], 16][[1]]; AppendTo[A294176, k]]; k++]; A294176 (* Robert G. Wilson v, Feb 11 2018 *)

Extensions

a(10) onward from Robert G. Wilson v, Feb 11 2018