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.

A184870 Numbers m such that prime(m) is of the form floor[(k-1/2)*(2+2^(1/2))+1/2]; complement of A184867.

Original entry on oeis.org

1, 3, 8, 10, 14, 16, 19, 21, 25, 26, 32, 35, 41, 44, 49, 53, 54, 58, 69, 71, 73, 79, 85, 87, 90, 93, 98, 100, 109, 112, 118, 121, 125, 128, 131, 132, 137, 138, 139, 141, 142, 149, 153, 159, 160, 161, 164, 169, 171, 174, 181, 182, 192, 196, 199, 202, 207, 209, 213, 218, 219, 221, 226, 228, 231, 235, 236, 240, 242, 246, 249, 255, 258, 259, 266, 267, 270, 273, 275, 277, 279, 280, 287, 292, 294, 297, 299, 303
Offset: 1

Views

Author

Clark Kimberling, Jan 23 2011

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_]:=Floor[(n-1/2)*(2+2^(1/2))+1/2];
    Table[a[n],{n,1,120}]  (* A063957 *)
    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,1,400}];t3
    (* Lists t1, t2, t3 match A184868, A184869, A184870. *)

A184865 Primes of the form floor(nr+h), where r=sqrt(2), h=1/2.

Original entry on oeis.org

3, 7, 11, 13, 17, 23, 31, 37, 41, 47, 59, 61, 71, 79, 83, 89, 103, 107, 109, 113, 127, 137, 139, 151, 157, 163, 167, 173, 181, 191, 197, 199, 211, 223, 229, 233, 239, 257, 263, 269, 277, 281, 283, 293, 307, 311, 313, 317, 331, 337, 349, 359, 373, 379, 383, 389, 397, 409, 419, 421, 431, 433, 443, 457, 461, 467, 479, 491, 499, 503, 509, 523, 547, 557, 563, 569, 571, 577, 587, 593, 601, 607, 617, 619, 631, 641, 643, 653, 659, 673, 677, 683, 701, 709, 727, 733, 751, 757, 761, 769, 809, 823, 827, 829, 839
Offset: 1

Views

Author

Clark Kimberling, Jan 23 2011

Keywords

Comments

See "conjecture generalized" at A184774.

Crossrefs

Programs

  • Mathematica
    r=2^(1/2); h=1/2; a[n_]:=Floor[n*r+h];
    Table[a[n],{n,1,120}] (* A022846, int. nearest 2^(1/2) *)
    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
    (* Lists t1, t2, t3 match A184865, A184866, A184867. *)
    Select[Floor[Sqrt[2]Range[1000]+1/2],PrimeQ] (* Harvey P. Dale, Oct 31 2011 *)
  • PARI
    lista(nn) = for (k=1, nn, if (isprime(p=floor(1/2+k*sqrt(2))), print1(p, ", "))); \\ Michel Marcus, Jan 30 2018

A184866 Numbers k such that floor(1/2+k*sqrt(2)) is prime.

Original entry on oeis.org

2, 5, 8, 9, 12, 16, 22, 26, 29, 33, 42, 43, 50, 56, 59, 63, 73, 76, 77, 80, 90, 97, 98, 107, 111, 115, 118, 122, 128, 135, 139, 141, 149, 158, 162, 165, 169, 182, 186, 190, 196, 199, 200, 207, 217, 220, 221, 224, 234, 238, 247, 254, 264, 268, 271, 275, 281, 289, 296, 298, 305, 306, 313, 323, 326, 330, 339, 347, 353, 356, 360, 370, 387, 394, 398, 402, 404, 408, 415, 419, 425, 429, 436, 438, 446, 453, 455, 462, 466, 476, 479, 483, 496, 501, 514, 518, 531, 535, 538, 544, 572, 582, 585, 586, 593
Offset: 1

Views

Author

Clark Kimberling, Jan 23 2011

Keywords

Crossrefs

Programs

  • Mathematica
    r=2^(1/2); h=1/2; a[n_]:=Floor[n*r+h];
    Table[a[n], {n, 1, 120}] (* A022846, int. nearest 2^(1/2) *)
    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
    (* Lists t1, t2, t3 match A184865, A184866, A184867. *)
  • PARI
    isok(k) = isprime(floor(1/2+k*sqrt(2))); \\ Michel Marcus, Jan 30 2018
Showing 1-3 of 3 results.