Numbers n such that Sum_{k=1..n} d(k) is an integer where d(k) is the decimal fraction 0.k (e.g. d(999)=0.999).

A054464

Numbers n such that Sum_{k=1..n} d(k) is an integer where d(k) is the decimal fraction 0.k (e.g. d(999)=0.999).

Terms

    a(0) =4a(1) =34a(2) =90a(3) =175a(4) =800a(5) =2999a(6) =3624a(7) =30624a(8) =60000a(9) =390624a(10) =499999a(11) =4000000a(12) =8890624a(13) =17109375a(14) =69999999a(15) =200000000a(16) =2787109375a(17) =8999999999a(18) =81787109375a(19) =900000000000

External references