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 A237526 a(n) = number of unit squares in the first quadrant of a disk of radius sqrt(n) centered at the origin of a square lattice. 1
 0, 0, 1, 1, 1, 3, 3, 3, 4, 4, 6, 6, 6, 8, 8, 8, 8, 10, 11, 11, 13, 13, 13, 13, 13, 15, 17, 17, 17, 19, 19, 19, 20, 20, 22, 22, 22, 24, 24, 24, 26, 28, 28, 28, 28, 30, 30, 30, 30, 30, 33, 33, 35, 37, 37, 37, 37, 37, 39, 39, 39, 41, 41, 41, 41, 45, 45, 45, 47, 47 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,6 LINKS FORMULA a(A000404(n)) = A232499(n). a(n) = Sum_{k=1..sqrt(n)} floor(sqrt(n-k^2)). - M. F. Hasler, Feb 09 2014 G.f.: (theta_3(x) - 1)^2/(4*(1 - x)), where theta_3() is the Jacobi theta function. - Ilya Gutkovskiy, Apr 17 2018 PROG (PARI) A237526(n)=sum(k=1, sqrtint(n), sqrtint(n-k^2)) \\ M. F. Hasler, Feb 09 2014 CROSSREFS Cf. A000404, A001481, A057961, A232499. Partial sums of A063725. Sequence in context: A120204 A177018 A156349 * A240117 A333536 A069941 Adjacent sequences:  A237523 A237524 A237525 * A237527 A237528 A237529 KEYWORD nonn,changed AUTHOR L. Edson Jeffery, Feb 09 2014 STATUS approved

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Last modified July 7 12:08 EDT 2022. Contains 355148 sequences. (Running on oeis4.)