A105575 Largest primes < numbers of the form 6k (duplicates removed).

5, 11, 17, 23, 29, 31, 41, 47, 53, 59, 61, 71, 73, 83, 89, 101, 107, 113, 131, 137, 139, 149, 151, 157, 167, 173, 179, 181, 191, 197, 199, 211, 227, 233, 239, 241, 251, 257, 263, 269, 271, 281, 283, 293, 311, 317, 331, 337, 347, 353, 359, 367, 373, 383, 389

Offset

1,1

Links

Table of n, a(n) for n=1..55.

Example

11 is in the sequence because 11 is the largest prime < 12 = 6*2.

Mathematica

PrevPrim[n_] := Block[{k = n - 1}, While[ !PrimeQ[k], k-- ]; k]; Union[ Table[ PrevPrim[6n], {n, 65}]] (* Robert G. Wilson v, May 21 2005 *)
NextPrime[#, -1]&/@(6*Range[100])//Union (* Harvey P. Dale, Sep 23 2017 *)

Crossrefs

Cf. A105399.

Sequence in context: A038939 A314243 A357253 * A314244 A314245 A314246

Adjacent sequences: A105572 A105573 A105574 * A105576 A105577 A105578

Keyword

easy,nonn

Author

Giovanni Teofilatto, May 03 2005

Extensions

Corrected and extended by Robert G. Wilson v, May 21 2005

Edited, corrected and extended by Ray Chandler, Oct 17 2006

Status

approved