A100032 Bisection of A005384.

3, 11, 29, 53, 89, 131, 179, 233, 251, 293, 419, 443, 509, 641, 659, 719, 761, 911, 1013, 1031, 1103, 1229, 1409, 1451, 1499, 1559, 1601, 1811, 1901, 1973, 2039, 2069, 2141, 2339, 2393, 2459, 2549, 2699, 2753, 2903, 2963, 3023, 3329, 3389, 3449, 3539, 3623

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..10431

Maple

A:={}: for n from 1 to 608 do if isprime(2*ithprime(n)+1)=true then A:=A union {ithprime(n)} else A:=A fi od: B:=convert(A, list): seq(B[2*j], j=1..nops(B)/2);

Mathematica

Select[Prime[Range[1000]], PrimeQ[2 #+1]&][[2;; ;; 2]] (* Vincenzo Librandi, Dec 24 2025 *)

Prog

(Magma) A := []; for n in [2..1000] do p := NthPrime(n); if IsPrime(2*p + 1) then
Append(~A, p); end if; end for; B := A; C := [ B[2*j-1] : j in [1..(#B div 2)] ]; C; // Vincenzo Librandi, Dec 24 2025

Crossrefs

Sequence in context: A196190 A111227 A111693 * A069350 A021005 A053845

Adjacent sequences: A100029 A100030 A100031 * A100033 A100034 A100035

Keyword

nonn,easy

Author

N. J. A. Sloane, Nov 20 2004

Extensions

More terms from Emeric Deutsch, Dec 09 2004

Status

approved