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A124262 a(1) = 2; for n > 1, a(n) is largest prime < 10*a(n-1). 4

%I #16 Sep 14 2015 14:59:09

%S 2,19,181,1801,17989,179849,1798487,17984833,179848309,1798483067,

%T 17984830667,179848306667,1798483066669,17984830666651,

%U 179848306666507,1798483066665031,17984830666650269,179848306666502647

%N a(1) = 2; for n > 1, a(n) is largest prime < 10*a(n-1).

%H Charles R Greathouse IV, <a href="/A124262/b124262.txt">Table of n, a(n) for n = 1..1000</a>, extending and correcting a b-file from Artur Jasinski

%t NestList[NextPrime[10 #, -1]&, 2, 20] (* _Vincenzo Librandi_, Jun 28 2014 *)

%o (PARI) step(k)=precprime(10*k)

%o t=1/5; vector(10,n,t=step(t)) \\ _Charles R Greathouse IV_, Sep 14 2015

%Y Cf. A006902, A040016, A120031-A120040, A126041.

%K nonn

%O 1,1

%A _Artur Jasinski_, Dec 16 2006

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Last modified March 28 16:12 EDT 2024. Contains 371254 sequences. (Running on oeis4.)