OFFSET
1,1
LINKS
Jinyuan Wang, Table of n, a(n) for n = 1..5000
R. W. K. Odoni, On the prime divisors of the sequence w_{n+1} = 1+w_1 ... w_n, J. London Math. Soc. 32 (1985), 1-11.
MAPLE
IsSylvester:=proc(p)
local x, S ; x:=2 : S:=NULL: while not member(x, [S]) do if x=0 then
return(true) fi; S := S , x; x := (x^2-x+1) mod p od : return false end:
L:=NULL:p:=5:while p<1000 do if not IsSylvester(p) then L:=L, p fi : p:=nextprime(p) od:
L;
# Robert FERREOL, Feb 14 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
Jeffrey Shallit, Aug 04 2004
EXTENSIONS
Definition corrected (following a remark by Don Reble) by M. F. Hasler, Apr 24 2014
STATUS
approved