0,1

Eric Weisstein's World of Mathematics, Repunit

P. De Geest, Repunits prime factors

a(n)=13 so 1111111111111 = 53*79*265371653.

Cf. A000042, A004022, A046053.

Adjacent sequences: A046411 A046412 A046413 this_sequence A046415 A046416 A046417

Sequence in context: A120273 A104817 A048450 this_sequence A023694 A038465 A103665

nonn,more,base

Patrick De Geest (pdg(AT)worldofnumbers.com), Jul 15 1998.