a(n) is the number of integers k less than 10^n such that the decimal representation of k lacks the digits 1,2,3,4 and 5 and at least one of digits 6,7,8,9.
A126642
a(n) is the number of integers k less than 10^n such that the decimal representation of k lacks the digits 1,2,3,4 and 5 and at least one of digits 6,7,8,9.
Terms
- a(0) =5a(1) =25a(2) =125a(3) =601a(4) =2765a(5) =12265a(6) =52925a(7) =223801a(8) =932525a(9) =3844105a(10) =15722525a(11) =63936601a(12) =258902285a(13) =1045109545a(14) =4209004925a(15) =16921851001a(16) =67945160045a(17) =272554432585
External references
- oeis: A126642