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.

A184810 Numbers m such that prime(m) has the form floor(k*r), where r=sqrt(2/3); complement of A184811.

Original entry on oeis.org

2, 3, 4, 8, 9, 10, 13, 14, 15, 17, 18, 19, 22, 23, 24, 26, 27, 28, 31, 34, 38, 39, 41, 42, 45, 46, 48, 49, 52, 53, 55, 56, 59, 60, 61, 66, 68, 72, 75, 76, 78, 79, 81, 82, 85, 86, 88, 89, 90, 92, 95, 96, 98, 99, 100, 102, 103, 106, 108, 109, 110, 112, 113, 114, 116, 117, 119, 120, 121, 122, 123, 124, 126, 128, 130, 131, 134, 135, 137, 139, 141, 142, 146, 147, 148, 149, 151, 152, 156, 157, 159, 162, 164, 165, 167, 168, 169, 170, 171, 173, 174, 175, 176, 177, 180
Offset: 1

Views

Author

Clark Kimberling, Jan 22 2011

Keywords

Crossrefs

Programs

  • Mathematica
    r=(2/3)^(1/2);s=(3/2)^(1/2); (* complementary because of joint ranking of i*sqrt(2) and j*sqrt(3) *)
    a[n_]:=n+Floor [n*r]; b[n_]:=n+Floor [n*s];
    Table[a[n],{n,1,120}]  (* A184808 *)
    Table[b[n],{n,1,120}]  (* A184809 *)
    t1={};Do[If[PrimeQ[a[n]], AppendTo[t1,a[n]]],{n,1,600}]
    t2={};Do[If[PrimeQ[a[n]], AppendTo[t2,n]],{n,1,600}]
    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}]
    t5={};Do[If[PrimeQ[b[n]], AppendTo[t5,n]],{n,1,600}]
    t6={};Do[If[MemberQ[t4,Prime[n]],AppendTo[t6,n]],{n,1,300}];t6
    (* t3 and t6 match A184810 and A184811 *)

A184809 a(n) = n + floor(sqrt(3/2)*n).

Original entry on oeis.org

2, 4, 6, 8, 11, 13, 15, 17, 20, 22, 24, 26, 28, 31, 33, 35, 37, 40, 42, 44, 46, 48, 51, 53, 55, 57, 60, 62, 64, 66, 68, 71, 73, 75, 77, 80, 82, 84, 86, 88, 91, 93, 95, 97, 100, 102, 104, 106, 109, 111, 113, 115, 117, 120, 122, 124, 126, 129, 131, 133, 135
Offset: 1

Views

Author

Clark Kimberling, Jan 22 2011

Keywords

Comments

This is the Beatty sequence for 1 + sqrt(3/2).
Also, a(n) is the position of 3*n^2 in the sequence obtained by arranging all the numbers in the sets {2*h^2, h >= 1} and {3*k^2, k >= 1} in increasing order. - Clark Kimberling, Oct 20 2014
Also, numbers n such that floor((n+1)*sqrt(6)) - floor(n*sqrt(6)) = 3. - Clark Kimberling, Jul 15 2015

Crossrefs

Complement of A184808.
Cf. A184811.

Programs

Formula

a(n) = n + floor(r*n), where r = sqrt(3/2).

A184808 n + floor(r*n), where r = sqrt(2/3); complement of A184809.

Original entry on oeis.org

1, 3, 5, 7, 9, 10, 12, 14, 16, 18, 19, 21, 23, 25, 27, 29, 30, 32, 34, 36, 38, 39, 41, 43, 45, 47, 49, 50, 52, 54, 56, 58, 59, 61, 63, 65, 67, 69, 70, 72, 74, 76, 78, 79, 81, 83, 85, 87, 89, 90, 92, 94, 96, 98, 99, 101, 103, 105, 107, 108, 110, 112, 114, 116
Offset: 1

Views

Author

Clark Kimberling, Jan 22 2011

Keywords

Comments

This is the Beatty sequence for 1 + sqrt(2/3).
Also, a(n) is the position of 2*n^2 in the sequence obtained by arranging all the numbers in the sets {2*h^2, h >= 1} and {3*k^2, k >= 1} in increasing order. - Clark Kimberling, Oct 20 2014
Also, numbers n such that floor((n+1)*sqrt(6)) - floor(n*sqrt(6)) = 2. - Clark Kimberling, Jul 15 2015

Crossrefs

Cf. A184809, A182760 (comment about joint ranking),

Programs

  • Magma
    [n+Floor(n*Sqrt(2/3)): n in [1..70]]; // Vincenzo Librandi, Oct 23 2014
    
  • Mathematica
    r=(2/3)^(1/2); s=(3/2)^(1/2);
    a[n_]:=n+Floor [n*r];
    b[n_]:=n+Floor [n*s];
    Table[a[n],{n,1,120}]  (* A184808 *)
    Table[b[n],{n,1,120}]  (* A184809 *)
  • PARI
    main(size)={return(vector(size, n, n+floor(sqrt(2/3)*n)))} /* Anders Hellström, Jul 15 2015 */

Formula

a(n) = n + floor(r*n), where r = sqrt(2/3).
Showing 1-3 of 3 results.