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%I #28 Jan 18 2022 02:29:59
%S 7,73,883,9931,99991,999961,9999973,99999589,999999193,9999999703,
%T 99999999763,999999999961,9999999998491,99999999999973,
%U 999999999997969,9999999999999643,99999999999998809,999999999999998929
%N Larger of the greatest twin prime pair with n digits.
%C Also the denominator of the largest prime over prime fraction less than 10^n.
%H Abhiram R Devesh, <a href="/A114429/b114429.txt">Table of n, a(n) for n = 1..100</a>
%F a(n) = A092250(n) + 2. - _M. F. Hasler_, Jan 17 2022
%o (Python)
%o import sympy
%o for i in range(1,100):
%o p=sympy.prevprime(10**i)
%o while not sympy.isprime(p-2):
%o p=sympy.prevprime(p)
%o print(p)
%o # _Abhiram R Devesh_, Aug 02 2014
%o (PARI)
%o a(n)=my(p=precprime(10^n)); while(!ispseudoprime(p-2),p=precprime(p-1)); return(p)
%o vector(50, n, a(n)) \\ _Derek Orr_, Aug 02 2014
%o (PARI) apply( {A114429(n,p=10^n)=until(2==p-p=precprime(p-1),);p+2}, [1..22]) \\ twice as fast by avoiding additional ispseudoprime(). - _M. F. Hasler_, Jan 17 2022
%o (Python)
%o from sympy import prevprime
%o def a(n):
%o p = prevprime(10**n); pp = prevprime(p)
%o while p - pp != 2: p, pp = pp, prevprime(pp)
%o return p
%o print([a(n) for n in range(1, 19)]) # _Michael S. Branicky_, Jan 17 2022
%Y Cf. A092250 (a(n)-2: lesser of the pair).
%K base,easy,nonn
%O 1,1
%A _Cino Hilliard_, Feb 13 2006
%E Corrected by _T. D. Noe_, Nov 15 2006
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