OFFSET
1,4
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
KEYWORD
nonn,easy
AUTHOR
Werner D. Sand, Aug 31 2002
STATUS
approved