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!)
 A070420 a(n) = 7^n mod 37. 2
 1, 7, 12, 10, 33, 9, 26, 34, 16, 1, 7, 12, 10, 33, 9, 26, 34, 16, 1, 7, 12, 10, 33, 9, 26, 34, 16, 1, 7, 12, 10, 33, 9, 26, 34, 16, 1, 7, 12, 10, 33, 9, 26, 34, 16, 1, 7, 12, 10, 33, 9, 26, 34, 16, 1, 7, 12, 10, 33, 9, 26, 34, 16, 1, 7, 12, 10, 33, 9, 26, 34, 16, 1, 7, 12, 10, 33, 9 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Sequence is periodic with length 9. Since a(18) = 1, 37 is composite in Z[sqrt(7)]: it can be factored as (10 - 3*sqrt(7))(10 + 3*sqrt(7)). - Alonso del Arte, Oct 12 2012 LINKS G. C. Greubel, Table of n, a(n) for n = 0..1000 Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,0,0,0,0,1). FORMULA From R. J. Mathar, Apr 20 2010: (Start) a(n) = a(n - 9). G.f.: ( -1 - 7*x - 12*x^2 - 10*x^3 - 33*x^4 - 9*x^5 - 26*x^6 - 34*x^7 - 16*x^8 ) / ( (x - 1)*(1 + x + x^2)*(x^6 + x^3 + 1) ). (End) EXAMPLE a(2) = 12 because 7^2 = 49 and 49 - 37 = 12. MATHEMATICA PowerMod[7, Range[0, 74], 37] (* Alonso del Arte, Oct 12 2012 *) PROG (Sage) [power_mod(7, n, 37) for n in range(0, 78)] # Zerinvary Lajos, Nov 27 2009 (PARI) a(n) = lift(Mod(7, 37)^n); \\ Michel Marcus, Mar 21 2016 (MAGMA) [Modexp(7, n, 37): n in [0..100]]; // Bruno Berselli, Mar 22 2016 CROSSREFS Sequence in context: A038598 A180570 A074474 * A223423 A274334 A328414 Adjacent sequences:  A070417 A070418 A070419 * A070421 A070422 A070423 KEYWORD nonn,easy 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 July 29 05:59 EDT 2021. Contains 346340 sequences. (Running on oeis4.)