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%I #20 Apr 01 2021 05:59:53
%S 2,7,47,1019,55414379
%N a(n) is the smallest prime p such that p, p - 1, p - 2, ..., p - n + 1 have 2, 4, 6, ..., 2*n divisors respectively.
%C a(n) is the smallest prime p such that tau(p) = tau(p - 1)/2 = tau(p - 2)/3 = ... = tau(p - n + 1)/n = 2, where tau(k) = the number of divisors of k (A000005).
%C No such prime p exists for n > 5, so a(5) is the final term. - _Jon E. Schoenfield_, Feb 07 2021
%H Jon E. Schoenfield, <a href="/A341214/a341214.txt">A proof that a(5) is the final term</a>
%e a(4) = 1019 because 1016, 1017, 1018 and 1019 have 8, 6, 4, and 2 divisors respectively and there is no smaller prime having this property (see A340872).
%Y Cf. A341213 (similar sequence for natural numbers).
%Y Cf. A000005, A294528, A340871, A340872.
%K nonn,fini,full
%O 1,1
%A _Jaroslav Krizek_, Feb 07 2021
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