A248198 - OEIS

A248198

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

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

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OFFSET

1,1

COMMENTS

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

LINKS

Table of n, a(n) for n=1..40.

MAPLE

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

MATHEMATICA

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

PROG

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

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

CROSSREFS

Cf. A228391 (similar, with floor).

Sequence in context: A026594 A240173 A235469 * A102296 A296807 A366310

Adjacent sequences: A248195 A248196 A248197 * A248199 A248200 A248201

KEYWORD

nonn,easy

AUTHOR

Juliann Barbella, Oct 03 2014

STATUS

approved