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

Author

Labos Elemer, Mar 23 2001

Keywords

• nonn
• easy

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

Crossrefs

Apart from initial term, same as A060308.

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

Programs

Haskell

a060265 = a007917 . (* 2)  -- Reinhard Zumkeller, Feb 22 2015

Maple

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

Mathematica

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

PARI

a(n) = precprime(2*n-1) \\ Harry J. Smith, Jul 03 2009