login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
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
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: A034935 A337833 A294948 * A121079 A270395 A105183
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 | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 29 08:08 EDT 2024. Contains 371265 sequences. (Running on oeis4.)