OFFSET
1,1
COMMENTS
Apart from the initial 3, the same as A049591. [Proof from T. Khovanova, Jan 23 2008: True for primes up to 5 by inspection. Higher primes must be of the form 6k+1 or 6k+5 since 6k+2 and 6k+4 are divisible by 2 and 6k+3 is divisible by 3. So searching the prime p backwards from the composite, odd 6k+3 in steps of 2 implies that p+2, skipped during that scan, is composite. So p is not in A001359 but in A049591.] - R. J. Mathar, Jan 28 2008
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
EXAMPLE
7 is in the sequence because 7 is the largest prime < 9=6*1+3.
MATHEMATICA
pp[n_] := Block[{k = n}, While[ ! PrimeQ[k], k-- ]; k]; Union[Table[pp[6n + 3], {n, 0, 65}]] (* Ray Chandler, Oct 17 2006 *)
Union[If[PrimeQ[#], #, NextPrime[#, -1]]&/@(6*Range[0, 70]+3)] (* Harvey P. Dale, Aug 20 2021 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Giovanni Teofilatto, May 01 2005
EXTENSIONS
Edited, corrected and extended by Ray Chandler, Oct 17 2006
STATUS
approved