OFFSET
1,2
LINKS
Ivan Neretin, Table of n, a(n) for n = 1..1000
MATHEMATICA
a[1]=1; a[n_]:=a[n]=(For[c=Sort[Table[a[k], {k, n-1}]]; d=Append[c, Last[c]+1]; m=First[Complement[Range[Last[d]], c]], MemberQ[c, m]||!PrimeQ[m*a[n-1]+1], m++ ]; m); Table[a[k], {k, 70}] (* Farideh Firoozbakht, Apr 14 2004 *)
PROG
(PARI) A073666(n, show=1, a=1, u=[a])={for(n=2, n, show&&print1(a", "); for(k=u[1]+1, 9e9, !setsearch(u, k) && isprime(a*k+1) && (a=k) && break); u=setunion(u, [a]); while(#u>1&&u[2]==u[1]+1, u=u[2..-1])); a} \\ Use 2nd, 3rd or 4th optional arg to display intermediate terms, to use another starting value, to exclude some terms. - M. F. Hasler, Nov 24 2015
CROSSREFS
KEYWORD
nonn
AUTHOR
Amarnath Murthy, Aug 10 2002
EXTENSIONS
More terms from Jason Earls, Aug 26 2002
Offset changed to 1 by Ivan Neretin, Mar 06 2016
STATUS
approved