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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

Table of n, a(n) for n=0..42.

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-Fran├žois 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

N. J. A. Sloane

EXTENSIONS

Revised Jun 28 2005

a(37)-a(42) from Vincenzo Librandi, Aug 21 2016

STATUS

approved

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Last modified August 20 06:32 EDT 2017. Contains 290824 sequences.