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 A348836 a(n) is the number of primes <= prime(n)^2/2. 2
 1, 2, 5, 9, 17, 23, 34, 41, 56, 81, 92, 124, 146, 157, 185, 222, 270, 283, 334, 368, 386, 444, 481, 548, 635, 681, 703, 753, 780, 832, 1013, 1068, 1160, 1192, 1345, 1376, 1472, 1577, 1648, 1752, 1864, 1899, 2090, 2129, 2197, 2240, 2492, 2749, 2837, 2881, 2976, 3107, 3159, 3389, 3540 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Michel Marcus, Table of n, a(n) for n = 1..2000 FORMULA a(n) = A000720(prime(n)^2/2). MATHEMATICA a[n_] := PrimePi[Prime[n]^2/2]; Array[a, 55] (* Amiram Eldar, Nov 01 2021 *) PROG (PARI) a(n) = primepi(prime(n)^2/2); CROSSREFS First column of A283235. Cf. A000040, A000720, A000879, A001248. Sequence in context: A059529 A271318 A119676 * A036711 A080740 A123324 Adjacent sequences: A348833 A348834 A348835 * A348837 A348838 A348839 KEYWORD nonn AUTHOR Michel Marcus, Nov 01 2021 STATUS approved

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Last modified March 30 07:09 EDT 2023. Contains 361606 sequences. (Running on oeis4.)