A126031 a(n) is the largest prime < 3*a(n-1) for n > 1, with a(1) = 2.

2, 5, 13, 37, 109, 317, 947, 2837, 8501, 25471, 76403, 229199, 687593, 2062759, 6188263, 18564769, 55694299, 167082893, 501248653, 1503745949, 4511237741, 13533713213, 40601139629, 121803418861, 365410256543, 1096230769619, 3288692308841, 9866076926507, 29598230779511

Offset: 1

Author

Artur Jasinski, Dec 16 2006

Keywords

• nonn

Links

• Artur Jasinski, Table of n, a(n) for n = 1..40

Crossrefs

Similar sequences for a(n) = largest prime < m*a(n-1): A006992 (m=2), this sequence (3), A124190 (4), A126033 (5), A126034 (6), A126035 (7), A126036 (8), A126037 (9), A124262 (10), A126039 (11), A126040 (12), A124339 (100), A124361 (1000), A124364 (10000), A124362 (100000), A124368 (1000000).

Programs

Mathematica

NestList[NextPrime[3#,-1]&,2,30] (* Harvey P. Dale, Feb 03 2012 *)