A124263 -id:A124263 - cp's OEIS frontend

A124262 a(n) is the largest prime < 10*a(n-1) for n > 1, with a(1) = 2.

2, 19, 181, 1801, 17989, 179849, 1798487, 17984833, 179848309, 1798483067, 17984830667, 179848306667, 1798483066669, 17984830666651, 179848306666507, 1798483066665031, 17984830666650269, 179848306666502647, 1798483066665026389, 17984830666650263887, 179848306666502638867

Offset: 1

Artur Jasinski, Dec 16 2006

nonn

Charles R Greathouse IV, Table of n, a(n) for n = 1..1000, extending and correcting a b-file from Artur Jasinski

Cf. A126031, A126041, A124475.
Sequences for other powers of 10: A124339 (100), A124361 (1000), A124364 (10000), A124362 (100000), A124368 (1000000).
Sequences for initial term k: A124263 (k=3), A124267 (5), A124291 (7), A124290 (11), A124298 (13), A124299 (17), A124336 (23), A124310 (29), A124335 (31), A124337 (37), A124338 (41).

NestList[NextPrime[10 #, -1]&, 2, 20] (* Vincenzo Librandi, Jun 28 2014 *)

step(k)=precprime(10*k)
my(t=1/5); vector(10,n,t=step(t)) \\ Charles R Greathouse IV, Sep 14 2015

A124310 Largest prime < 10*a(n-1), a(1)=29.

Original entry on oeis.org

29, 283, 2819, 28183, 281807, 2818043, 28180393, 281803927, 2818039241, 28180392407, 281803924067, 2818039240619, 28180392406171, 281803924061641, 2818039240616359, 28180392406163579, 281803924061635783, 2818039240616357827, 28180392406163578069, 281803924061635780589

Offset: 1

Artur Jasinski, Dec 16 2006, corrected Jan 25 2007

nonn

Practically the same as A124263. - R. J. Mathar, Jun 18 2008

Vincenzo Librandi, Table of n, a(n) for n = 1..200

Cf. A124262, A124263.

NestList[NextPrime[10#,-1]&,29,20] (* Harvey P. Dale, Aug 19 2011 *)

A124357 Largest prime < 100*a(n-1), a(1)=3.

Original entry on oeis.org

3, 293, 29297, 2929699, 292969877, 29296987651, 2929698765083, 292969876508291, 29296987650829069, 2929698765082906837, 292969876508290683679, 29296987650829068367867, 2929698765082906836786649, 292969876508290683678664841, 29296987650829068367866484043

Offset: 1

Artur Jasinski, Dec 16 2006

nonn

Cf. A124262, A124263, A124339.

NestList[NextPrime[100#,-1]&,3,15] (* Harvey P. Dale, Oct 05 2011 *)

More terms from Harvey P. Dale, Oct 05 2011

cp's OEIS Frontend

A124262 a(n) is the largest prime < 10*a(n-1) for n > 1, with a(1) = 2.

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A124310 Largest prime < 10*a(n-1), a(1)=29.

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A124357 Largest prime < 100*a(n-1), a(1)=3.

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