Consecutive Smith numbers. The first few Smith brothers are (728, 729), (2964, 2965), (3864, 3865), (4959, 4960), ... (OEIS A050219 and A050220).
Smith Brothers
See also
Smith NumberExplore with Wolfram|Alpha
References
Sloane, N. J. A. Sequences A050219 and A050220 in "The On-Line Encyclopedia of Integer Sequences."Referenced on Wolfram|Alpha
Smith BrothersCite this as:
Weisstein, Eric W. "Smith Brothers." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/SmithBrothers.html