This site is supported by donations to The OEIS Foundation.

 Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing. Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A070409 a(n) = 7^n mod 23. 1
 1, 7, 3, 21, 9, 17, 4, 5, 12, 15, 13, 22, 16, 20, 2, 14, 6, 19, 18, 11, 8, 10, 1, 7, 3, 21, 9, 17, 4, 5, 12, 15, 13, 22, 16, 20, 2, 14, 6, 19, 18, 11, 8, 10, 1, 7, 3, 21, 9, 17, 4, 5, 12, 15, 13, 22, 16, 20, 2, 14, 6, 19, 18, 11, 8, 10, 1, 7, 3, 21, 9, 17, 4, 5, 12, 15, 13, 22, 16, 20 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Periodic with period 22. - Joerg Arndt, Feb 24 2015 LINKS Index entries for linear recurrences with constant coefficients, signature (1, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 1). FORMULA From R. J. Mathar, Apr 20 2010: (Start) a(n) = a(n-1) - a(n-11) + a(n-12). G.f.: ( -1 - 6*x + 4*x^2 - 18*x^3 + 12*x^4 - 8*x^5 + 13*x^6 - x^7 - 7*x^8 - 3*x^9 + 2*x^10 - 10*x^11 ) / ( (x-1)*(1+x)*(x^10 - x^9 + x^8 - x^7 + x^6 - x^5 + x^4 - x^3 + x^2 - x + 1) ). (End) a(n) = A000420(n) mod 23. - Michel Marcus, Feb 24 2015 MATHEMATICA Table[PowerMod[7, n, 23], {n, 0, 79}] (* Alonso del Arte, Feb 23 2015 *) CoefficientList[Series[(- 1 - 6 x + 4 x^2 - 18 x^3 + 12 x^4 - 8 x^5 + 13 x^6 - x^7 - 7 x^8 - 3 x^9 + 2 x^10 - 10 x^11) / ((x - 1) (1 + x) (x^10 - x^9 + x^8 - x^7 + x^6 - x^5 + x^4 - x^3 + x^2 - x + 1)), {x, 0, 80}], x] (* Vincenzo Librandi, Feb 26 2015 *) LinearRecurrence[{1, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 1}, {1, 7, 3, 21, 9, 17, 4, 5, 12, 15, 13, 22}, 80] (* Ray Chandler, Aug 27 2015 *) PROG (Sage) [power_mod(7, n, 23) for n in range(0, 80)] # Zerinvary Lajos, Nov 27 2009 (PARI) a(n) = lift(Mod(7, 23)^n); \\ Michel Marcus, Feb 23 2015 (MAGMA) I:=[1, 7, 3, 21, 9, 17, 4, 5, 12, 15, 13, 22]; [n le 12 select I[n] else Self(n-1)-Self(n-11)+Self(n-12): n in [1..70]]; // Vincenzo Librandi, Feb 26 2015 (MAGMA) [Modexp(7, n, 23): n in [0..100]]; // Bruno Berselli, Mar 22 2016 CROSSREFS Sequence in context: A160797 A050013 A161417 * A166481 A050012 A271573 Adjacent sequences:  A070406 A070407 A070408 * A070410 A070411 A070412 KEYWORD nonn,easy,changed AUTHOR N. J. A. Sloane, May 12 2002 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 04:15 EST 2019. Contains 329885 sequences. (Running on oeis4.)