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A052404 Numbers without 2 as a digit. 14
0, 1, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14, 15, 16, 17, 18, 19, 30, 31, 33, 34, 35, 36, 37, 38, 39, 40, 41, 43, 44, 45, 46, 47, 48, 49, 50, 51, 53, 54, 55, 56, 57, 58, 59, 60, 61, 63, 64, 65, 66, 67, 68, 69, 70, 71, 73, 74, 75, 76, 77, 78, 79, 80, 81, 83, 84, 85, 86, 87, 88, 89 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,3
REFERENCES
M. J. Halm, Word Weirdness, Mpossibilities 66 (Feb. 1998), p. 5.
LINKS
M. J. Halm, Games
M. F. Hasler, Numbers avoiding certain digits, OEIS Wiki, Jan 12 2020.
FORMULA
If the offset were changed to 0: a(0) = 0, a(n+1) = f(a(n)+1,f(a(n)+1) where f(x,y) = if x<10 and x<>2 then y else if x mod 10 = 2 then f(y+1,y+1) else f(floor(x/10),y). - Reinhard Zumkeller, Mar 02 2008
a(n) = replace digits d > 1 by d + 1 in base-9 representation of n - 1. - Reinhard Zumkeller, Oct 07 2014
Sum_{k>1} 1/a(k) = A082831 = 19.257356... (Kempner series). - Bernard Schott, Jan 12 2020, edited by M. F. Hasler, Jan 14 2020
MAPLE
a:= proc(n) local l, m; l, m:= 0, n-1;
while m>0 do l:= (d->
`if`(d<2, 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
ban2Q[n_]:=FreeQ[IntegerDigits[n], 2]==True; Select[Range[0, 89], ban2Q[#] &] (* Jayanta Basu, May 17 2013 *)
Select[Range[0, 100], DigitCount[#, 10, 2]==0&] (* Harvey P. Dale, Apr 13 2015 *)
PROG
(Magma) [ n: n in [0..89] | not 2 in Intseq(n) ]; // Bruno Berselli, May 28 2011
(sh) seq 0 1000 | grep -v 2; # Joerg Arndt, May 29 2011
(Haskell)
a052404 = f . subtract 1 where
f 0 = 0
f v = 10 * f w + if r > 1 then r + 1 else r where (w, r) = divMod v 9
-- Reinhard Zumkeller, Oct 07 2014
(PARI) lista(nn, d=2) = {for (n=0, nn, if (!vecsearch(vecsort(digits(n), , 8), d), print1(n, ", ")); ); } \\ Michel Marcus, Feb 21 2015
(PARI)
apply( {A052404(n)=fromdigits(apply(d->d+(d>1), digits(n-1, 9)))}, [1..99])
next_A052404(n, d=digits(n+=1))={for(i=1, #d, d[i]==2&&return((1+n\d=10^(#d-i))*d)); n} \\ least a(k) > n: if there's a digit 2 in n+1, replace the first occurrence by 3 and all following digits by 0.
(A052404_vec(N)=vector(N, i, N=if(i>1, next_A052404(N))))(99) \\ first N terms
select( {is_A052404(n)=!setsearch(Set(digits(n)), 2)}, [0..99])
(A052404_upto(N)=select( is_A052404, [0..N]))(99) \\ M. F. Hasler, Jan 11 2020
CROSSREFS
Cf. A004177, A004721, A072809, A082831 (Kempner series).
Cf. A052382 (without 0), A052383 (without 1), A052405 (without 3), A052406 (without 4), A052413 (without 5), A052414 (without 6), A052419 (without 7), A052421 (without 8), A007095 (without 9).
See A038604 for the subset of primes. - M. F. Hasler, Jan 11 2020
Sequence in context: A026511 A321153 A304814 * A298112 A026417 A026421
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 10:19 EDT 2024. Contains 372926 sequences. (Running on oeis4.)