A073518 Cotangent of Pi/prime(n), rounded to nearest integer.

0, 1, 1, 2, 3, 4, 5, 6, 7, 9, 10, 12, 13, 14, 15, 17, 19, 19, 21, 23, 23, 25, 26, 28, 31, 32, 33, 34, 35, 36, 40, 42, 44, 44, 47, 48, 50, 52, 53, 55, 57, 58, 61, 61, 63, 63, 67, 71, 72, 73, 74, 76, 77, 80, 82, 84, 86, 86, 88, 89, 90, 93, 98, 99, 100, 101, 105, 107, 110, 111, 112

Offset

1,4

Links

Table of n, a(n) for n=1..71.

Formula

a(n) = round(cotan(Pi/prime(n))) or a(n) = round(1/tan(Pi/prime(n))).

Example

For n=8: prime(8)=19; cotan(Pi/19) = 5.9926... => 6.

Mathematica

Table[Round[Cot[Pi/Prime[n]]], {n, 71}] (* Jayanta Basu, Jul 01 2013 *)

Prog

(PARI) a(n)=if(n>1, round(1/tan(Pi/prime(n))), 0) \\ Charles R Greathouse IV, Jul 01 2013

Crossrefs

Sequence in context: A039163 A125299 A063949 * A144769 A165737 A349996

Adjacent sequences: A073515 A073516 A073517 * A073519 A073520 A073521

Keyword

nonn,easy

Author

Werner D. Sand, Aug 31 2002

Status

approved