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

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

Author

Clark Kimberling, Jan 23 2011

Keywords

• nonn

Links

• G. C. Greubel, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A184774, A184868, A184870.

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