A102177 Iccanobirt semiprime indices (7 of 15): Indices of semiprime numbers in A102117.
5, 9, 22, 29, 33, 38, 41, 54, 60, 71, 82, 100, 107, 175, 180, 193, 217, 258, 259, 282, 295, 360, 382
Offset: 1
Programs
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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 *)
Extensions
a(17) from Robert Price, Nov 09 2018
Offset changed to 1 and a(18)-a(23) from Jinyuan Wang, Aug 12 2021