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.

A184867 Numbers m such that prime(m) is of the form floor(1/2+k*sqrt(2)). Complement of A184870.

Original entry on oeis.org

2, 4, 5, 6, 7, 9, 11, 12, 13, 15, 17, 18, 20, 22, 23, 24, 27, 28, 29, 30, 31, 33, 34, 36, 37, 38, 39, 40, 42, 43, 45, 46, 47, 48, 50, 51, 52, 55, 56, 57, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 70, 72, 74, 75, 76, 77, 78, 80, 81, 82, 83, 84, 86, 88, 89, 91, 92, 94, 95, 96, 97, 99, 101, 102, 103, 104, 105, 106, 107, 108, 110, 111, 113, 114, 115, 116, 117, 119, 120, 122, 123, 124, 126, 127, 129, 130, 133, 134, 135, 136, 140, 143, 144, 145, 146
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. *)

A184868 Primes of the form floor((k-1/2)*(2+sqrt(2))+1/2); i.e., primes in A063957.

Original entry on oeis.org

2, 5, 19, 29, 43, 53, 67, 73, 97, 101, 131, 149, 179, 193, 227, 241, 251, 271, 347, 353, 367, 401, 439, 449, 463, 487, 521, 541, 599, 613, 647, 661, 691, 719, 739, 743, 773, 787, 797, 811, 821, 859, 883, 937, 941, 947, 971, 1009, 1019, 1033, 1087, 1091, 1163, 1193, 1217, 1231, 1279, 1289, 1303, 1361, 1367, 1381, 1429, 1439, 1453, 1483, 1487, 1511, 1531, 1559, 1579, 1613, 1627, 1637, 1699, 1709, 1733, 1753, 1777, 1787, 1801, 1811, 1873, 1907, 1931, 1951, 1979, 1999
Offset: 1

Views

Author

Clark Kimberling, Jan 23 2011

Keywords

Comments

See "conjecture generalized" at A184774.

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. *)
  • PARI
    lista(nn) = for (k=1, nn, if (isprime(p=floor((k-1/2)*(2+sqrt(2))+1/2)), print1(p, ", "))); \\ Michel Marcus, Jan 30 2018

A184869 Numbers k such that floor[(k-1/2)*(2+2^(1/2))+1/2] is prime.

Original entry on oeis.org

1, 2, 6, 9, 13, 16, 20, 22, 29, 30, 39, 44, 53, 57, 67, 71, 74, 80, 102, 104, 108, 118, 129, 132, 136, 143, 153, 159, 176, 180, 190, 194, 203, 211, 217, 218, 227, 231, 234, 238, 241, 252, 259, 275, 276, 278, 285, 296, 299, 303, 319, 320, 341, 350, 357, 361, 375, 378, 382, 399, 401, 405, 419, 422, 426, 435, 436, 443, 449, 457, 463, 473, 477, 480, 498, 501, 508, 514, 521, 524, 528, 531, 549, 559, 566, 572, 580, 586
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. *)
  • PARI
    isok(k) = isprime(floor((k-1/2)*(2+sqrt(2))+1/2)); \\ Michel Marcus, Jan 30 2018
Showing 1-3 of 3 results.