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 A000413 Let A(n) = #{(i,j,k): i^2 + j^2 + k^2 <= n}, V(n) = (4/3)Pi*n^(3/2), P(n) = A(n) - V(n); A000092 gives values of n where |P(n)| sets a new record; sequence gives A(A000092(n)). (Formerly M4367 N1833) 5
 1, 7, 19, 57, 81, 251, 437, 691, 739, 1743, 3695, 6619, 8217, 9771, 14771, 15155, 16831, 18805, 26745, 30551, 41755, 46297, 54339, 72359, 86407, 96969, 131059, 344859, 395231, 519963, 607141, 677397, 741509, 893019, 917217, 1288415, 1406811, 1789599, 1827927, 3085785, 3216051, 3444439, 3524869 (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 W. C. Mitchell, The number of lattice points in a k-dimensional hypersphere, Math. Comp., 20 (1966), 300-310. MATHEMATICA P[n_] := (s = Sum[SquaresR[3, k], {k, 0, n}]) - Round[(4/3)*Pi*n^(3/2)]; record = 0; A000092 = Join[{1}, Reap[For[n = 1, n <= 10^4, n++, If[(p = Abs[P[n]]) > record, record = p; Print[s]; Sow[s]]]][[2, 1]]] (* Jean-François Alcover, Feb 08 2016, after M. F. Hasler in A000092 *) CROSSREFS Cf. A000323, A000036, A000092, A000099, A000223. Sequence in context: A002714 A126361 A069005 * A263335 A155335 A155226 Adjacent sequences:  A000410 A000411 A000412 * A000414 A000415 A000416 KEYWORD nonn AUTHOR EXTENSIONS Revised Jun 28 2005 a(37)-a(42) from Vincenzo Librandi, Aug 21 2016 STATUS approved

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Last modified March 26 04:32 EDT 2019. Contains 321481 sequences. (Running on oeis4.)