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 A296021 Number of primes of the form 4*k+1 <= 4*n+1. 6
 0, 1, 1, 2, 3, 3, 3, 4, 4, 5, 6, 6, 6, 7, 7, 8, 8, 8, 9, 9, 9, 9, 10, 10, 11, 12, 12, 13, 14, 14, 14, 14, 14, 14, 15, 15, 15, 16, 16, 17, 17, 17, 17, 18, 18, 19, 19, 19, 20, 21, 21, 21, 21, 21, 21, 21, 21, 22, 23, 23, 24, 24, 24, 24, 25, 25, 25, 26, 26, 27, 28, 28 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 LINKS Seiichi Manyama, Table of n, a(n) for n = 0..10000 PROG (Ruby) require 'prime' def A(k, n) ary = [] cnt = 0 k.step(4 * n + k, 4){|i| cnt += 1 if i.prime? ary << cnt } ary end p A(1, 100) CROSSREFS Cf. A016813, A091098, A295996, A296020. Sequence in context: A305845 A120565 A244989 * A267097 A194198 A189674 Adjacent sequences: A296018 A296019 A296020 * A296022 A296023 A296024 KEYWORD nonn AUTHOR Seiichi Manyama, Dec 02 2017 STATUS approved

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Last modified October 2 22:30 EDT 2023. Contains 365841 sequences. (Running on oeis4.)