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 A000690 Landau's approximation to population of x^2 + y^2. (Formerly M0586 N0212) 2
 1, 2, 3, 4, 7, 13, 24, 44, 83, 157, 297, 567, 1085, 2086, 4019, 7766, 15039, 29181, 56717, 110408, 215225, 420076, 820836, 1605587, 3143562, 6160098, 12080946, 23710229, 46565965, 91512121, 179947985, 354043613, 696935548, 1372589372 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 REFERENCES N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence). N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). LINKS Sean A. Irvine, Table of n, a(n) for n = 0..999 D. Shanks, The second-order term in the asymptotic expansion of B(x), Mathematics of Computation 18 (1964), pp. 75-86. FORMULA a(n) = round(b*2^n/sqrt(log(2^n))) where b=0.764223654... is the Landau-Ramanujan constant (A064533). CROSSREFS Cf. A064533. Sequence in context: A137495 A099779 A270440 * A049876 A049795 A014251 Adjacent sequences:  A000687 A000688 A000689 * A000691 A000692 A000693 KEYWORD nonn AUTHOR EXTENSIONS More terms from Sean A. Irvine, Feb 23 2011 STATUS approved

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Last modified October 22 05:29 EDT 2019. Contains 328315 sequences. (Running on oeis4.)