OFFSET
1,3
COMMENTS
From the proof of Sir John Wilson's theorem:
numbers of sets of stellated p-gons.
REFERENCES
G. E. Andrews, Number Theory, 1971, Dover Publications New York, p 39.
FORMULA
a(n)=((Prime[n] - 1)! - (Prime[n] - 1))/(2*Prime[n]).
MATHEMATICA
f[n_] = ((Prime[n] - 1)! - (Prime[n] - 1))/(2*Prime[n]); Table[f[n], {n, 1, 20}]
((#-1)!-#+1)/(2#)&/@Prime[Range[20]] (* Harvey P. Dale, Aug 12 2016 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Roger L. Bagula and Gary W. Adamson, Aug 25 2008
STATUS
approved