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 A025694 Index of 2^n within sequence of numbers of form 2^i * 9^j. 1
 1, 2, 3, 4, 6, 8, 10, 13, 16, 19, 23, 27, 31, 36, 41, 46, 52, 58, 64, 70, 77, 84, 91, 99, 107, 115, 124, 133, 142, 152, 162, 172, 183, 194, 205, 217, 229, 241, 253, 266, 279, 292, 306, 320, 334, 349, 364, 379, 395, 411, 427, 444, 461, 478, 496, 514, 532, 550, 569, 588, 607 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Robert Israel, Table of n, a(n) for n = 0..10000 MAPLE f:= proc(n) local j, s, t;       t:= n;       for j from 1 do          s:= ilog2(9^j);          if s >= n then return t fi;          t:= t + n-1-s;       od end proc: map(f, [\$1..100]); # Robert Israel, Dec 09 2016 PROG (PARI) a(n)=my(N=1); n+1+sum(i=1, n, logint(N<<=1, 9)); \\ Charles R Greathouse IV, Jan 11 2018 (PARI) first(n)=my(s, N=1/2); vector(n+1, i, s+=logint(N<<=1, 9)+1) \\ Charles R Greathouse IV, Jan 11 2018 CROSSREFS Sequence in context: A008739 A280706 A025695 * A022796 A008748 A089649 Adjacent sequences:  A025691 A025692 A025693 * A025695 A025696 A025697 KEYWORD nonn,easy AUTHOR EXTENSIONS Offset corrected by Charles R Greathouse IV, Jan 11 2018 STATUS approved

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Last modified August 25 13:50 EDT 2019. Contains 326324 sequences. (Running on oeis4.)