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 A076068 Smallest number that can be formed by using the nonzero digits of the numbers 1+n(n-1)/2 through n(n+1)/2. 4
 1, 23, 456, 1789, 1111112345, 11111226789, 22222222345678, 122333333334569, 12333344444445789, 1234444455555556789, 123455555666666666789, 12345666677777777777889, 112345677888888888889999 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Is there any r and s such that a(r) = a(s)? Probably not. LINKS EXAMPLE a(4) = 1789 (=01789) formed by using digits of 7,8,9 and 10. MATHEMATICA sncbf[n_]:=Sort[Flatten[IntegerDigits/@Range[(n(n-1))/2+1, (n(n+1))/2]]/.(0->Nothing)]//FromDigits; Array[sncbf, 15] (* Harvey P. Dale, Nov 26 2019 *) CROSSREFS Cf. A080479, A080480. Sequence in context: A291128 A174262 A174425 * A062273 A066547 A001369 Adjacent sequences:  A076065 A076066 A076067 * A076069 A076070 A076071 KEYWORD base,nonn AUTHOR Amarnath Murthy, Oct 05 2002 EXTENSIONS More terms from David Wasserman, Mar 19 2005 STATUS approved

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Last modified September 28 17:43 EDT 2020. Contains 337393 sequences. (Running on oeis4.)