# On a problem of Cusick concerning the sum of digits of *n* and *n+t*

## M. Drmota, M. Kauers, L. Spiegelhofer

- deq.txt -- guessed differential equation for the
diagonal of F(x,y,z) in Section 4.3
- rec.txt -- guessed recurrence equation for the
diagonal of F(x,y,z) in Section 4.3
- taylor.sws -- Sage worksheet about the Taylor expansion in Section 4.3
- P.m -- telescoper for
*U(x,y)* in Section 5.2
- Q.m -- certificate for
*U(x,y)* in Section 5.2