Search: id:A055558 Results 1-1 of 1 results found. %I A055558 %S A055558 19,199,1999,199999,19999999,199999999999999999999999999, %T A055558 1999999999999999999999999999, %U A055558 199999999999999999999999999999999999999999999999999999 %N A055558 Primes of form 1999...999. %F A055558 a(n)=2*10^n-1 and is prime %e A055558 2*10^n-1 is prime for {1,2,3,5,7,26,27,53,147,236,248,386,401} n gives how many digit 9 occurs in these numbers %Y A055558 A051200. %Y A055558 Sequence in context: A067272 A037071 A065582 this_sequence A160452 A113596 A155670 %Y A055558 Adjacent sequences: A055555 A055556 A055557 this_sequence A055559 A055560 A055561 %K A055558 base,nonn %O A055558 1,1 %A A055558 Labos E. (labos(AT)ana.sote.hu), Jul 10 2000 Search completed in 0.001 seconds