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 A052405 Numbers without 3 as a digit. 17
 0, 1, 2, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 24, 25, 26, 27, 28, 29, 40, 41, 42, 44, 45, 46, 47, 48, 49, 50, 51, 52, 54, 55, 56, 57, 58, 59, 60, 61, 62, 64, 65, 66, 67, 68, 69, 70, 71, 72, 74, 75, 76, 77, 78, 79, 80, 81, 82, 84, 85, 86, 87, 88, 89 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS This sequence also represents the minimal number of straight lines of a covering tree to cover n X n points arranged in a symmetrical grid. - Marco Ripà, Sep 20 2018 LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..10000 M. F. Hasler, Numbers avoiding certain digits, OEIS Wiki, Jan 12 2020. Index entries for 10-automatic sequences. FORMULA a(n) >> n^k with k = log(10)/log(9) = 1.0479.... - Charles R Greathouse IV, Oct 16 2012 a(n) = replace digits d > 2 by d + 1 in base-9 representation of n - 1. - Reinhard Zumkeller, Oct 07 2014 Sum_{n>1} 1/a(n) = A082832 = 20.569877... (Kempner series). - Bernard Schott, Jan 12 2020, edited by M. F. Hasler, Jan 14 2020 EXAMPLE 22 has no 3s among its digits, hence it is in the sequence. 23 has one 3 among its digits, hence it is not in the sequence. MAPLE a:= proc(n) local l, m; l, m:= 0, n-1; while m>0 do l:= (d-> `if`(d<3, d, d+1))(irem(m, 9, 'm')), l od; parse(cat(l))/10 end: seq(a(n), n=1..100); # Alois P. Heinz, Aug 01 2016 MATHEMATICA Select[Range[0, 89], DigitCount[#, 10, 3] == 0 &] (* Alonso del Arte, Oct 16 2012 *) PROG (Magma) [ n: n in [0..89] | not 3 in Intseq(n) ]; // Bruno Berselli, May 28 2011 (sh) seq 0 1000 | grep -v 3; # Joerg Arndt, May 29 2011 (PARI) is(n)=n=digits(n); for(i=1, #n, if(n[i]==3, return(0))); 1 \\ Charles R Greathouse IV, Oct 16 2012 apply( {A052405(n)=fromdigits(apply(d->d+(d>2), digits(n-1, 9)))}, [1..99]) \\ a(n) next_A052405(n, d=digits(n+=1))={for(i=1, #d, d[i]==3&& return((1+n\d=10^(#d-i))*d)); n} \\ least a(k) > n. Used in A038611. \\ M. F. Hasler, Jan 11 2020 (Haskell) a052405 = f . subtract 1 where f 0 = 0 f v = 10 * f w + if r > 2 then r + 1 else r where (w, r) = divMod v 9 -- Reinhard Zumkeller, Oct 07 2014 CROSSREFS Cf. A004178, A004722, A038611 (subset of primes), A082832 (Kempner series). Cf. A052382 (without 0), A052383 (without 1), A052404 (without 2), A052406 (without 4), A052413 (without 5), A052414 (without 6), A052419 (without 7), A052421 (without 8), A007095 (without 9). Cf. A011533 (complement). Sequence in context: A133016 A026503 A235498 * A039212 A039221 A183297 Adjacent sequences: A052402 A052403 A052404 * A052406 A052407 A052408 KEYWORD base,easy,nonn AUTHOR Henry Bottomley, Mar 13 2000 EXTENSIONS Offset changed by Reinhard Zumkeller, Oct 07 2014 STATUS approved

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Last modified May 29 08:50 EDT 2024. Contains 372926 sequences. (Running on oeis4.)