1,2

Table of n, a(n) for n=1..10.

Joe K. Crump, The 9 Nines

Index entries for similar sequences

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.

Sequence in context: A052661 A225117 A088624 * A006173 A102055 A232376

Adjacent sequences: A066406 A066407 A066408 * A066410 A066411 A066412

more,nonn

Joe K. Crump (joecr(AT)carolina.rr.com), Dec 24 2001

Corrected by Leonhard Vogt (leonhard.vogt(AT)gmx.ch), Jan 09 2006

approved