A256421 Odd numbers and twice primes, sorted.

1, 3, 4, 5, 6, 7, 9, 10, 11, 13, 14, 15, 17, 19, 21, 22, 23, 25, 26, 27, 29, 31, 33, 34, 35, 37, 38, 39, 41, 43, 45, 46, 47, 49, 51, 53, 55, 57, 58, 59, 61, 62, 63, 65, 67, 69, 71, 73, 74, 75, 77, 79, 81, 82, 83, 85, 86, 87, 89, 91, 93, 94

Offset

1,2

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Formula

a(n) ~ 2n. - Charles R Greathouse IV, Apr 07 2015

Mathematica

Select[Range@94, PrimeQ[#/2]||OddQ[#]&] (* Ivan N. Ianakiev, Apr 08 2015 *)

Prog

(PARI) lista(nn) = nb = primepi(nn)\2; vecsort(setunion(vector(prime(nb), n, 2*n-1), 2*primes(nb))); \\ Michel Marcus, Apr 07 2015
(PARI) list(lim)=setunion(vector((lim+1)\2, i, 2*i-1), 2*primes([2, lim])) \\ Charles R Greathouse IV, Apr 07 2015

Crossrefs

Cf. A256420.

Sequence in context: A039133 A113777 A285659 * A253200 A227938 A039096

Adjacent sequences: A256418 A256419 A256420 * A256422 A256423 A256424

Keyword

nonn

Author

N. J. A. Sloane, Apr 07 2015

Status

approved