This site is supported by donations to The OEIS Foundation.

 Annual Appeal: Please make a donation to keep the OEIS running. In 2018 we replaced the server with a faster one, added 20000 new sequences, and reached 7000 citations (often saying "discovered thanks to the OEIS"). Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A079339 Least k such that the decimal representation of k*n contains only 1's and 0's. 32
 1, 5, 37, 25, 2, 185, 143, 125, 12345679, 1, 1, 925, 77, 715, 74, 625, 653, 61728395, 579, 5, 481, 5, 4787, 4625, 4, 385, 40781893, 3575, 37969, 37, 3581, 3125, 3367, 3265, 286, 308641975, 3, 2895, 259, 25, 271, 2405, 25607, 25, 24691358, 23935, 213, 23125 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS From David Amar (dpamar(AT)gmail.com), Jul 12 2010: (Start) This sequence is well defined. In the n+1 first repunits (see A002275), there are at least 2 numbers that have the same value modulo n (Pigeonhole principle). The difference between those two numbers contains only 1's and 0's in decimal representation. (End) REFERENCES Popular Computing (Calabasas, CA), Z-Sequences, Vol. 4 (No. 34, A pr 1976), pages PC36-4 to PC37-6, but there are many errors (cf. A257343, A257344). LINKS Robert G. Wilson v, Table of n, a(n) for n = 1..10000 First 1999 terms from T. D. Noe and the next 7999 terms from N. J. A. Sloane [Based on A004290]. FORMULA a(n) = A004290(n)/n. a(n) < 10^(n+1) / (9n). - Charles R Greathouse IV, Jan 09 2012 EXAMPLE 3*37=111 and no integer k<37 has this property, hence a(3)=37. PROG (PARI) d(n, i)=floor(n/10^(i-1))-10*floor(n/10^i); test(n)=sum(i=1, ceil(log(n)/log(10)), if(d(n, i)*(1-d(n, i)), 1, 0)); a(n)=if(n<0, 0, s=1; while(test(n*s)>0, s++); s) CROSSREFS Cf. A004290, A070189, A078241-A078248, A096681-A096688, A257343, A257344, A257345. Sequence in context: A174507 A119483 A157809 * A257343 A244927 A043075 Adjacent sequences:  A079336 A079337 A079338 * A079340 A079341 A079342 KEYWORD base,nonn AUTHOR Benoit Cloitre, Feb 13 2003 EXTENSIONS More terms from Vladeta Jovovic and Matthew Vandermast, Feb 14 2003 Definition simplified by Franklin T. Adams-Watters, Jan 09 2012 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified December 10 17:32 EST 2018. Contains 318049 sequences. (Running on oeis4.)