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 A302434 Number of primes of the form b^2 + 2 for b <= 10^n. 3
 4, 12, 69, 447, 3423, 27869, 236985, 2054022, 18127693, 162237123 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS From Jacques Tramu, Sep 13 2018: (Start) Table C(i) = a(i)/(n*log(n)), with n = 10^i: a(1) = 4 C(1) = 0.92103404 a(2) = 12 C(2) = 0.55262042 a(3) = 69 C(3) = 0.47663511 a(4) = 447 C(4) = 0.41170221 a(5) = 3423 C(5) = 0.39408744 a(6) = 27869 C(6) = 0.38502446 a(7) = 236985 C(7) = 0.38197469 a(8) = 2054022 C(8) = 0.37836484 a(9) = 18127693 C(9) = 0.37566500 a(10) = 162237123 C(10) = 0.37356478 (End) LINKS Table of n, a(n) for n=1..10. EXAMPLE a(1) = 4 because there are 4 primes of the form b^2+2 for b <= 10: 2, 3, 11 and 83. PROG (PARI) {a(n) = sum(k=0, 10^n, isprime(k^2+2))} CROSSREFS Number of primes of the form b^2+m for b <= 10^n: A302443 (m=-3), A302442 (m=-2), A206709 (m=1), this sequence (m=2), A302435 (m=3). Cf. A056899. Sequence in context: A369284 A358409 A180386 * A121771 A009621 A335907 Adjacent sequences: A302431 A302432 A302433 * A302435 A302436 A302437 KEYWORD nonn,more AUTHOR Seiichi Manyama, Apr 07 2018 EXTENSIONS a(10) from Jacques Tramu, Sep 13 2018 STATUS approved

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