The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A178769 a(n) = (5*10^n + 13)/9. 3
 2, 7, 57, 557, 5557, 55557, 555557, 5555557, 55555557, 555555557, 5555555557, 55555555557, 555555555557, 5555555555557, 55555555555557, 555555555555557, 5555555555555557, 55555555555555557, 555555555555555557 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 LINKS Bruno Berselli, Table of n, a(n) for n = 0..1000. Bruno Berselli, A property that includes the numbers of the form 5..57. Index entries for linear recurrences with constant coefficients, signature (11,-10). FORMULA a(n)^(4*k+2) + 1 == 0 (mod 250)  for n>1, k>=0. G.f.: (2-15*x)/((1-x)*(1-10*x)). a(n) - 11*a(n-1) + 10*a(n-2) = 0 (n>1). a(n) = a(n-1) + 5*10^(n-1) = 10*a(n-1) - 13 for n>0. a(n) = 1 + Sum_{i=0..n} A093143(i). - Bruno Berselli, Feb 16 2015 MATHEMATICA CoefficientList[Series[(2 - 15 x) / ((1 - x) (1 - 10 x)), {x, 0, 20}], x] (* Vincenzo Librandi, Jun 06 2013 *) LinearRecurrence[{11, -10}, {2, 7}, 20] (* Harvey P. Dale, Feb 28 2017 *) PROG (MAGMA) [(5*10^n+13)/9: n in [0..20]]; // Vincenzo Librandi, Jun 06 2013 (PARI) vector(20, n, n--; (5*10^n+13)/9) \\ G. C. Greubel, Jan 24 2019 (Sage) [(5*10^n+13)/9 for n in (0..20)] # G. C. Greubel, Jan 24 2019 (GAP) List([0..20], n -> (5*10^n+13)/9); # G. C. Greubel, Jan 24 2019 CROSSREFS Cf. A165246 (..17, 117, 1117,..), A173193 (..27, 227, 2227,..), A173766 (..37, 337, 3337,..), A173772 (..47, 447, 4447,..), A067275 (..67, 667, 6667,..), A002281 (..77, 777, 7777,..), A173812 (..87, 887, 8887,..), A173833 (..97, 997, 9997,..). Cf. A093143. Sequence in context: A048898 A034935 A294948 * A121079 A270395 A105183 Adjacent sequences:  A178766 A178767 A178768 * A178770 A178771 A178772 KEYWORD nonn,easy AUTHOR Bruno Berselli, Jun 13 2010 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 February 27 13:18 EST 2020. Contains 332306 sequences. (Running on oeis4.)