OFFSET
1,2
COMMENTS
LINKS
Thomas Clausen, Theorem. Lehrsatz aus einer Abhandlung ueber die Bernoullischen Zahlen, Astr. Nachr. 17 (22) (1840), 351-352.
MATHEMATICA
(* This program is not convenient for more than 15 terms *) c[n_] := Sum[Boole[PrimeQ[d+1]]/(d+1), {d, Divisors[n]}] // Denominator; Reap[For[n = 1, n < 10^7, n++, If[Divisible[c[3*n], n], Print[n]; Sow[n]]]][[2, 1]] (* Jean-François Alcover, May 21 2013 *)
PROG
(PARI)
A212197_list(searchlimit) =
{
for (n=1, searchlimit,
p = 1;
fordiv(3*n, d,
r = d + 1;
if (isprime(r), p = p*r; )
);
if (Mod(p, n) == 0, print1(n, ", "));
);
}
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Peter Luschny, May 05 2012
STATUS
approved