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A009993
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Numbers whose decimal digits are in strictly increasing order.
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15
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0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 12, 13, 14, 15, 16, 17, 18, 19, 23, 24, 25, 26, 27, 28, 29, 34, 35, 36, 37, 38, 39, 45, 46, 47, 48, 49, 56, 57, 58, 59, 67, 68, 69, 78, 79, 89, 123, 124, 125, 126, 127, 128, 129, 134, 135, 136, 137, 138, 139, 145, 146, 147, 148, 149, 156, 157
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OFFSET
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1,3
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COMMENTS
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Sequence has 512 terms, since every term except 0 corresponds to a nonempty subset of {1,2,3,4,5,6,7,8,9}.
A178788(a(n)) = 1. - Reinhard Zumkeller, Jun 30 2010
Number of terms in [10^(n-1), 10^n): 0, 9, 36, 84, 126, 126, 84, 36, 9, 1. - Robert G. Wilson v, Jul 20 2014
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LINKS
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Zak Seidov, Table of n, a(n) for n = 1..512 (full sequence)
Eric Weisstein's World of Mathematics, Digit
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MATHEMATICA
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Flatten@Table[FromDigits/@Subsets[Range[1, 9], {n}], {n, 0, 9}] (* Zak Seidov, May 19 2006 *)
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PROG
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(PARI) is_A009993(n)=Set(n=digits(n))==n \\ M. F. Hasler, Dec 11 2019
(PARI) forsubset(9, s, print1(fromdigits(Vec(s))", ")) \\ M. F. Hasler, Dec 11 2019
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CROSSREFS
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Cf. A009995.
Sequence in context: A032881 A239216 A032848 * A190218 A055569 A351119
Adjacent sequences: A009990 A009991 A009992 * A009994 A009995 A009996
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KEYWORD
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nonn,fini,full,base
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AUTHOR
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N. J. A. Sloane
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STATUS
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approved
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