OFFSET
1,1
MATHEMATICA
nxt[{a_, b_, c_}]:={b, c, Total[IntegerReverse/@{a, b, c}]}; Flatten[ Position[ NestList[nxt, {0, 0, 1}, 220][[All, 1]], _?(PrimeOmega[#] == 2&)]]-1 (* Harvey P. Dale, Dec 30 2018 *)
CROSSREFS
KEYWORD
nonn,more,less,base
AUTHOR
Jonathan Vos Post and Ray Chandler, Dec 31 2004
EXTENSIONS
a(17) from Robert Price, Nov 09 2018
Offset changed to 1 and a(18)-a(23) from Jinyuan Wang, Aug 12 2021
STATUS
approved