A100031 Bisection of A005384.

2, 5, 23, 41, 83, 113, 173, 191, 239, 281, 359, 431, 491, 593, 653, 683, 743, 809, 953, 1019, 1049, 1223, 1289, 1439, 1481, 1511, 1583, 1733, 1889, 1931, 2003, 2063, 2129, 2273, 2351, 2399, 2543, 2693, 2741, 2819, 2939, 2969, 3299, 3359, 3413, 3491, 3593

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..41118

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-1], j=1..nops(B)/2);

Mathematica

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

Prog

(Magma) [primes[i] : i in [1..#primes by 2]] where primes := [p : p in PrimesUpTo(5000) | IsPrime(2*p+1)]; // Vincenzo Librandi, Dec 24 2025

Crossrefs

Cf. A005384, A100032.

Sequence in context: A141181 A191030 A233074 * A293213 A215278 A126975

Adjacent sequences: A100028 A100029 A100030 * A100032 A100033 A100034

Keyword

nonn,easy

Author

N. J. A. Sloane, Nov 20 2004

Extensions

More terms from Emeric Deutsch, Dec 09 2004

Status

approved