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 A000693 Related to population of numbers of form x^2 + y^2. (Formerly M0767 N0292) 0
 1, 2, 3, 6, 10, 19, 35, 62, 118, 219, 414, 783, 1497, 2860, 5503, 10593, 20471, 39637, 76918, 149501, 291115, 567581, 1108022, 2165621, 4237085, 8297727, 16264207, 31904254, 62630372, 123031586, 241837446, 475647114, 936020000, 1842925873 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 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 Table of n, a(n) for n=1..34. D. Shanks, The second-order term in the asymptotic expansion of B(x), Mathematics of Computation 18 (1964), pp. 75-86. Index entries for sequences related to populations of quadratic forms FORMULA a(1)=1, a(2)=2, a(n) = A000074(n) + a(n-2) for n > 2. CROSSREFS Sequence in context: A227309 A368279 A123916 * A054178 A005833 A247162 Adjacent sequences: A000690 A000691 A000692 * A000694 A000695 A000696 KEYWORD nonn AUTHOR N. J. A. Sloane EXTENSIONS More terms from Sean A. Irvine, Feb 24 2011 STATUS approved

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Last modified July 13 04:46 EDT 2024. Contains 374267 sequences. (Running on oeis4.)