A217573 - OEIS

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A217573

Number of integers between -(2*n+1)*Pi and (2*n+2)*Pi.

10, 22, 34, 47, 60, 72, 84, 98, 110, 122, 135, 148, 160, 172, 186, 198, 210, 223, 236, 248, 260, 274, 286, 298, 311, 324, 336, 348, 362, 374, 386, 399, 412, 424, 436, 450, 462, 474, 487, 500, 512, 524, 538, 550, 562, 575, 588, 600, 612, 626, 638, 650, 663 (list; graph; refs; listen; history; text; internal format)

	OFFSET	`0,1`
	COMMENTS	`a(n) is the number of lattice points inside spiral r=theta and on X-axis counted until the (n+1)-th loop of the spiral.`
	LINKS	`Table of n, a(n) for n=0..52.` `César Eliud Lozada, Plot of spiral`
	FORMULA	`a(n) = floor((2n+1)Pi) + floor((2n+2)Pi) + 1.`
	MAPLE	`A := []:` `for n from 0 to 80 do` `n1 := floor((2n+1)Pi):` `n2 := floor((2n+2)Pi):` `A := [op(A), n1+n2+1]` `end do:` `A:=A;`
	MATHEMATICA	`Table[Ceiling[Pi(2n+2)]+Floor[Pi(2n+1)], {n, 0, 60}] (* Harvey P. Dale, Aug 25 2014 *)`
	CROSSREFS	`Cf. A001951.` `Sequence in context: A339003 A017641 A232540 * A276626 A211482 A177791` `Adjacent sequences: A217570 A217571 A217572 * A217574 A217575 A217576`
	KEYWORD	`nonn`
	AUTHOR	`César Eliud Lozada, Oct 08 2012`
	STATUS	`approved`

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Last modified May 21 00:36 EDT 2022. Contains 353886 sequences. (Running on oeis4.)