a(n) is the smallest positive integer k such that k*R_n has digits with alternating parity, where R_n is the n-th repunit.

A391473

a(n) is the smallest positive integer k such that k*R_n has digits with alternating parity, where R_n is the n-th repunit.

Terms

    a(0) =1a(1) =11a(2) =19a(3) =371a(4) =1891a(5) =36911a(6) =189091a(7) =3690911a(8) =18909091a(9) =369090911a(10) =1890909091a(11) =36909090911a(12) =189090909091

External references