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 A262557 Numbers with digits in strictly decreasing order, sorted lexicographically. 6
 0, 1, 10, 2, 20, 21, 210, 3, 30, 31, 310, 32, 320, 321, 3210, 4, 40, 41, 410, 42, 420, 421, 4210, 43, 430, 431, 4310, 432, 4320, 4321, 43210, 5, 50, 51, 510, 52, 520, 521, 5210, 53, 530, 531, 5310, 532, 5320, 5321, 53210, 54, 540, 541, 5410, 542, 5420, 5421 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS Original name: "Countdown sequences, allowing gaps." Only digits 0 through 9 are used. The last term is 9876543210. Equals A009995, sorted lexicographically. - Reinhard Zumkeller, Oct 14 2015 There are 2^k terms starting with digit k >= 0, they start at index 2^k. The countdown sequences, i.e., digits of the n-th term, are given in rows of A272011. - M. F. Hasler, Dec 11 2019 REFERENCES Donald S. McDonald, Email message to N. J. A. Sloane, Oct 14 2015. LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..1023 FORMULA a(n) = A009995(A263328(n)); a(A263327(n)) = A009995(n). - Reinhard Zumkeller, Oct 15 2015 PROG (Haskell) a262557 n = a262557_list !! (n-1) a262557_list = 0 : f [[0]] where    f xss = if x < 9 then (map (read . concatMap show) zss) ++ f zss else []            where zss = (map (z :) \$ map tail xss) ++ (map (z :) xss)                  z = x + 1; x = head \$ head xss -- Reinhard Zumkeller, Oct 14 2015 From M. F. Hasler, Dec 11 2019: (Start) (PARI) is_A262557 = is_A009995 apply( A262557(n)=fromdigits(Vecrev(vecextract([0..exponent(n+!n)], n))), [1..99]) # A262557=concat(apply(x(i)=concat(vector(i%10+1, j, if(j>1, x(i*10+j-2), i))), [0..9])) \\ (End) CROSSREFS Cf. A009995, A263327, A263328. Sequence in context: A173237 A319154 A086068 * A030595 A232590 A094715 Adjacent sequences:  A262554 A262555 A262556 * A262558 A262559 A262560 KEYWORD nonn,base,fini,full AUTHOR N. J. A. Sloane, Oct 14 2015 EXTENSIONS New name from M. F. Hasler, Dec 11 2019 STATUS approved

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Last modified February 26 05:51 EST 2020. Contains 332277 sequences. (Running on oeis4.)