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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A184586 a(n) = floor((n-1/2)*r), where r=sqrt(5); complement of A184587.

Original entry on oeis.org

1, 3, 5, 7, 10, 12, 14, 16, 19, 21, 23, 25, 27, 30, 32, 34, 36, 39, 41, 43, 45, 48, 50, 52, 54, 57, 59, 61, 63, 65, 68, 70, 72, 74, 77, 79, 81, 83, 86, 88, 90, 92, 95, 97, 99, 101, 103, 106, 108, 110, 112, 115, 117, 119, 121, 124, 126, 128, 130, 133, 135, 137, 139, 141, 144, 146, 148, 150, 153, 155, 157, 159, 162, 164, 166, 168, 171, 173, 175, 177, 180, 182, 184, 186, 188, 191, 193, 195, 197, 200, 202, 204, 206, 209, 211, 213, 215, 218, 220, 222, 224, 226, 229, 231, 233, 235, 238, 240, 242, 244, 247, 249, 251, 253, 256, 258, 260, 262, 264, 267
Offset: 1

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Author

Clark Kimberling, Jan 17 2011

Keywords

Comments

r = sqrt(5) and s = (5+sqrt(5))/4 form a Beatty pair. This yields the pair of complementary homogeneous Beatty sequences A022839 and A108598. From a theorem of Thoralf Skolem follows that (a(n)) and A184587 are complementary inhomogeneous Beatty sequences. - Michel Dekking, Sep 08 2017

Crossrefs

Cf. A184587.

Programs

  • Mathematica
    r=5^(1/2); c=1/2; s=r/(r-1);
    Table[Floor[n*r-c*r],{n,1,120}]  (* A184586 *)
    Table[Floor[n*s+c*s],{n,1,120}]  (* A184587 *)

Formula

a(n)=floor[(n-1/2)r], where r=sqrt(5).

Extensions

Name and formula corrected by Michel Dekking, Sep 08 2017

A077545 Primes of the form floor(k*e).

Original entry on oeis.org

2, 5, 13, 19, 29, 43, 59, 67, 73, 89, 97, 103, 127, 149, 157, 163, 173, 179, 233, 239, 241, 263, 269, 271, 277, 293, 307, 331, 337, 347, 353, 383, 421, 443, 467, 521, 557, 587, 617, 619, 641, 701, 709, 733, 739, 761, 769, 823, 829, 839, 853, 883, 907, 929, 937
Offset: 1

Views

Author

Amarnath Murthy, Nov 09 2002

Keywords

Comments

Primes not in A077545 are in A184856, since {floor(k*e)} and {floor(j*e/(e-1))} are complementary Beatty sequences (A022843 and A054385).

Crossrefs

Programs

  • Mathematica
    r=E; s=r/(r-1);
    a[n_]:=Floor[n*r];
    b[n_]:=Floor[n*s];
    Table[a[n], {n, 1, 120}]  (* A022843 *)
    t1={}; Do[If[PrimeQ[a[n]], AppendTo[t1, a[n]]], {n, 1, 600}]; t1
    t2={}; Do[If[PrimeQ[a[n]], AppendTo[t2, n]], {n, 1, 600}]; t2
    t3={}; Do[If[MemberQ[t1, Prime[n]], AppendTo[t3, n]], {n, 1, 300}]; t3
    t4={}; Do[If[PrimeQ[b[n]], AppendTo[t4, b[n]]], {n, 1, 600}]; t4
    t5={}; Do[If[PrimeQ[b[n]], AppendTo[t5, n]], {n, 1, 600}]; t5
    t6={}; Do[If[MemberQ[t4, Prime[n]], AppendTo[t6, n]], {n, 1, 300}]; t6
    (* List t1 matches A077545; list t2 matches A062409;
    lists t3-t6 match A184855-A184858. *)

Extensions

More terms from Sascha Kurz, Jan 12 2003
Mathematica code and crossreferences by Clark Kimberling, Jan 24 2011
Showing 1-2 of 2 results.