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 A336298 Greatest prime < prime(n)/2. 2
 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, 53, 53, 53, 61, 61, 67, 67, 73, 73, 73, 79, 83, 83, 89, 89, 89, 89, 97, 97, 103, 109, 113, 113, 113, 113, 113, 113, 127, 131, 131, 131, 137, 139, 139, 139, 151, 151 (list; graph; refs; listen; history; text; internal format)
 OFFSET 3,1 COMMENTS The n-th prime appears A102820(n) times. - Flávio V. Fernandes, Apr 08 2021 LINKS FORMULA a(n) = A151799(A000040(n)/2) for n >= 3. - Wesley Ivan Hurt, Nov 26 2020 EXAMPLE Prime(3)/2 = 2.5, so that a(3) = 2. MATHEMATICA z = 120; t = Table[NextPrime[Prime[n]/2], {n, 3, z}]; (* A039734, A079953 *) u = NextPrime[t, -1]  (* A336298 *) t - u (* A336299 *) Table[NextPrime[Prime[n]/2, -1], {n, 3, 80}] (* Wesley Ivan Hurt, Nov 26 2020 *) PROG (PARI) a(n) = precprime(prime(n)/2); \\ Michel Marcus, Nov 16 2020 (Python) from sympy import prime, prevprime def A336298(n):     return prevprime(prime(n)//2+1) # Chai Wah Wu, Nov 26 2020 CROSSREFS Cf. A000040, A039734, A336299. Sequence in context: A234345 A111060 A082432 * A037153 A323185 A168065 Adjacent sequences:  A336295 A336296 A336297 * A336299 A336300 A336301 KEYWORD nonn,changed AUTHOR Clark Kimberling, Nov 16 2020 STATUS approved

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Last modified April 21 03:28 EDT 2021. Contains 343145 sequences. (Running on oeis4.)