A060265 Largest prime less than 2n.

3, 5, 7, 7, 11, 13, 13, 17, 19, 19, 23, 23, 23, 29, 31, 31, 31, 37, 37, 41, 43, 43, 47, 47, 47, 53, 53, 53, 59, 61, 61, 61, 67, 67, 71, 73, 73, 73, 79, 79, 83, 83, 83, 89, 89, 89, 89, 97, 97, 101, 103, 103, 107, 109, 109, 113, 113, 113, 113, 113, 113, 113, 127, 127, 131

Offset

2,1

Comments

a(n) = A007917(2*n) = A255313(n-1,1) = A255316(n-1,1) = A006530(A255427(n)). - Reinhard Zumkeller, Feb 22 2015

Links

Harry J. Smith, Table of n, a(n) for n = 2..1000

Maple

seq (prevprime(2*i+1), i=2..256);

Mathematica

Table[NextPrime[2 n, -1], {n, 2, 66}] (* Michael De Vlieger, Jul 04 2016 *)

Prog

(PARI) a(n) = precprime(2*n-1) \\ Harry J. Smith, Jul 03 2009
(Haskell)
a060265 = a007917 . (* 2)  -- Reinhard Zumkeller, Feb 22 2015

Crossrefs

Apart from initial term, same as A060308.

Cf. A020482, A049653, A088631, A007917, A005843, A255313.

Sequence in context: A037464 A302564 A335046 * A172365 A297709 A242999

Adjacent sequences: A060262 A060263 A060264 * A060266 A060267 A060268

Keyword

nonn,easy

Author

Labos Elemer, Mar 23 2001

Status

approved