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 A066409 Least positive integer not representable using exactly n 9's and the operations +-*/(). 0
 1, 2, 1, 4, 13, 22, 33, 103, 195, 381 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Joe K. Crump, The 9 Nines EXAMPLE a(4)=4 because 4 cannot be expressed with exactly 4 nines and the operations +-*/(). E.g. 1 = 9/9+9-9, 2 = 9/9+9/9, 3 = (9+9+9)/9, but 4 has no such representation. 138 = (((9 - (9 / ((9 + 9) + 9))) * (9 + 9)) - 9) - 9. 265 = ((((9 - (9 / (9 + 9))) + 9) + 9) * ((9 * 9) + 9)) / 9. CROSSREFS Sequence in context: A052661 A225117 A088624 * A006173 A102055 A232376 Adjacent sequences:  A066406 A066407 A066408 * A066410 A066411 A066412 KEYWORD more,nonn AUTHOR Joe K. Crump (joecr(AT)carolina.rr.com), Dec 24 2001 EXTENSIONS Corrected by Leonhard Vogt (leonhard.vogt(AT)gmx.ch), Jan 09 2006 STATUS approved

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Last modified January 20 23:20 EST 2019. Contains 319343 sequences. (Running on oeis4.)