This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A336298 #48 Jun 05 2023 01:13:30
%S A336298 2,3,5,5,7,7,11,13,13,17,19,19,23,23,29,29,31,31,31,37,41,43,47,47,47,
%T A336298 53,53,53,61,61,67,67,73,73,73,79,83,83,89,89,89,89,97,97,103,109,113,
%U A336298 113,113,113,113,113,127,131,131,131,137,139,139,139,151,151
%N A336298 Greatest prime < prime(n)/2.
%C A336298 The n-th prime appears A102820(n) times. - _Flávio V. Fernandes_, Apr 08 2021
%C A336298 A080191 lists the distinct terms of this sequence. - _Flávio V. Fernandes_, Jun 19 2021
%F A336298 a(n) = A151799(A000040(n)/2) for n >= 3. - _Wesley Ivan Hurt_, Nov 26 2020
%e A336298 Prime(3)/2 = 2.5, so a(3) = 2.
%t A336298 z = 120; t = Table[NextPrime[Prime[n]/2], {n, 3, z}]; (* A039734, A079953 *)
%t A336298 u = NextPrime[t, -1] (* A336298 *)
%t A336298 t - u (* A336299 *)
%t A336298 Table[NextPrime[Prime[n]/2, -1], {n, 3, 80}] (* _Wesley Ivan Hurt_, Nov 26 2020 *)
%o A336298 (PARI) a(n) = precprime(prime(n)/2); \\ _Michel Marcus_, Nov 16 2020
%o A336298 (Python)
%o A336298 from sympy import prime, prevprime
%o A336298 def A336298(n):
%o A336298 return prevprime(prime(n)//2+1) # _Chai Wah Wu_, Nov 26 2020
%Y A336298 Cf. A000040, A039734, A336299.
%K A336298 nonn
%O A336298 3,1
%A A336298 _Clark Kimberling_, Nov 16 2020