OFFSET
1,2
FORMULA
a(n) = 0 (mod 3) for n >= 2.
a(n) = 0 or 12 (mod 15) for n >= 3.
MAPLE
PROG
(PARI) A190911(n)=n*=n+3; forprime(p=3, , if(n%p, return(p)))
{my(v=[0], t=3, p=5);
print1("1, 3");
forprime(q=7, 1000,
u=vector(#v);
for(i=1, #u,
u[i]=lift(chinese(Mod(v[i], t), Mod( 0, p)));
v[i]=lift(chinese(Mod(v[i], t), Mod(-3, p)))
);
v=vecsort(concat(u, v));
for(j=2, #v,
if(A190911(v[j])==q,
print1(", "v[j]);
break
)
);
t*=p;
p=q
)} \\ Charles R Greathouse IV, Oct 09 2011
CROSSREFS
KEYWORD
nonn
AUTHOR
Nathaniel Johnston, May 26 2011
EXTENSIONS
a(11)-a(22) from Charles R Greathouse IV, Oct 09 2011
STATUS
approved