OFFSET
1,1
MATHEMATICA
nxt[{a_, b_, c_}]:={b, c, IntegerReverse[c+IntegerReverse[b]+IntegerReverse[a]]}; Flatten[ Position[NestList[nxt, {0, 0, 1}, 800][[;; , 1]], _?(PrimeOmega[#]==2&)]-1] (* Harvey P. Dale, Mar 23 2023 *)
CROSSREFS
KEYWORD
nonn,more,less,base
AUTHOR
Jonathan Vos Post and Ray Chandler, Dec 31 2004
EXTENSIONS
Offset changed to 1 and a(21)-a(31) from Jinyuan Wang, Aug 14 2021
STATUS
approved