Pensieve Header: What happens when you repeatedly add a number to its decimal “reverse”?

op[n_]:=FromDigits[Reverse@IntegerDigits[n]]

pal[n_] := NestWhileList[(#+op[#])&, n, (#≠op[#])&]

pal[9998]

pal[99998]

Sort[(Length[pal[#]]->#)& /@ Range[100]] // Last

pal[98]

Print[pal[#]]& /@ Range[200]

pal[196]

Just the first 100 results:

NestWhileList[(Print[#]; #+op[#])&, 196, (#≠op[#])&,1,100]