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A102177 Iccanobirt semiprime indices (7 of 15): Indices of semiprime numbers in A102117. 1
5, 9, 22, 29, 33, 38, 41, 54, 60, 71, 82, 100, 107, 175, 180, 193, 217, 258, 259, 282, 295, 360, 382 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
A102117(a(n)) = A102197(n).
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
Sequence in context: A146476 A110200 A063404 * A299266 A219521 A215178
KEYWORD
nonn,more,less,base
AUTHOR
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

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Last modified July 13 21:44 EDT 2024. Contains 374288 sequences. (Running on oeis4.)