Juliann Barbella - cp's OEIS frontend

A248469 a(n) = floor((2*n^2)/e).

0, 2, 6, 11, 18, 26, 36, 47, 59, 73, 89, 105, 124, 144, 165, 188, 212, 238, 265, 294, 324, 356, 389, 423, 459, 497, 536, 576, 618, 662, 707, 753, 801, 850, 901, 953, 1007, 1062, 1119, 1177, 1236, 1297, 1360, 1424, 1489, 1556, 1625, 1695, 1766, 1839

Offset: 1

Juliann Barbella, Oct 06 2014

Cf. A032635 (floor(n^2/e)).

int a(int n) {return (int) ((2*Math.pow(x, 2))/Math.exp(1.0)); }

Table[Floor[(2 n^2)/ E ], {n, 1, 60}] (* Vincenzo Librandi, Oct 23 2014 *)

a(n) = (2*n^2)\exp(1) \\ Michel Marcus, Oct 25 2014

a(n) = floor((2*n^2)/e).

More terms from Vincenzo Librandi, Oct 23 2014

A248758 Ceiling(n*Pi^(1/3)).

Original entry on oeis.org

0, 2, 3, 5, 6, 8, 9, 11, 12, 14, 15, 17, 18, 20, 21, 22, 24, 25, 27, 28, 30, 31, 33, 34, 36, 37, 39, 40, 42, 43, 44, 46, 47, 49, 50, 52, 53, 55, 56, 58, 59, 61, 62, 63, 65, 66, 68, 69, 71, 72, 74, 75, 77, 78, 80, 81, 83, 84, 85, 87, 88, 90, 91, 93, 94, 96

Offset: 0

Juliann Barbella, Oct 13 2014

Cube root of the volume of a cylinder with radius and height n rounded up to the nearest integer. - Wesley Ivan Hurt, Oct 13 2014

Cf. A240977 (similar, with floor).

static int a(int n) {return (int) Math.ceil(n*Math.pow(Math.PI, (1.0/3))); }

[Ceiling(n*Pi(RealField(100))^(1/3)) : n in [0..100]]; // Wesley Ivan Hurt, Oct 13 2014

A248758:=n->ceil(n*Pi^(1/3)): seq(A248758(n), n=0..100); # Wesley Ivan Hurt, Oct 13 2014

Table[Ceiling[n*Pi^(1/3)], {n, 0, 100}] (* Wesley Ivan Hurt, Oct 13 2014 *)

a(n) = ceiling(n*Pi^(1/3)).

a(n) = A240977(n)+1 for all n>0. - M. F. Hasler, Oct 14 2014

A248198 a(n) = ceiling(n^3*(Pi/2)).

Original entry on oeis.org

2, 13, 43, 101, 197, 340, 539, 805, 1146, 1571, 2091, 2715, 3452, 4311, 5302, 6434, 7718, 9161, 10775, 12567, 14548, 16726, 19112, 21715, 24544, 27609, 30918, 34483, 38311, 42412, 46796, 51472, 56450, 61739, 67348, 73288, 79566, 86193, 93179, 100531

Offset: 1

Juliann Barbella, Oct 03 2014

a(n) is the ceiling of the area of a square with diagonal n times the circumference of a circle with diameter n. - Wesley Ivan Hurt, Oct 03 2014

a(n) is also the ceiling of the volume of a cylinder with radius n and height n/2. Equivalently, a(n) is the ceiling of the volume of a cylinder with diameter n and height 2*n. - Derek Orr, Oct 03 2014

Cf. A228391 (similar, with floor).

int a(int n) {return (int) Math.ceil(Math.pow(n, 3)*Math.PI/(2)); }

A248198:=n->ceil(n^3*(Pi/2)): seq(A248198(n), n=1..40); # Wesley Ivan Hurt, Oct 03 2014

Table[Ceiling[n^3*(Pi/2)], {n, 40}] (* Wesley Ivan Hurt, Oct 03 2014 *)

vector(100,n,ceil(n^3*Pi/2)) \\ Derek Orr, Oct 03 2014

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User: Juliann Barbella

A248469 a(n) = floor((2*n^2)/e).

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A248758 Ceiling(n*Pi^(1/3)).

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A248198 a(n) = ceiling(n^3*(Pi/2)).

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