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A248198
a(n) = ceiling(n^3*(Pi/2)).
1
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
1,1
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
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
KEYWORD
nonn,easy
AUTHOR
Juliann Barbella, Oct 03 2014
STATUS
approved