This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A238470 Period 7: repeat [0, 0, 1, 0, 0, -1, 0]. 5
 0, 0, 1, 0, 0, -1, 0, 0, 0, 1, 0, 0, -1, 0, 0, 0, 1, 0, 0, -1, 0, 0, 0, 1, 0, 0, -1, 0, 0, 0, 1, 0, 0, -1, 0, 0, 0, 1, 0, 0, -1, 0, 0, 0, 1, 0, 0, -1, 0, 0, 0, 1, 0, 0, -1, 0, 0, 0, 1, 0, 0, -1, 0, 0, 0, 1, 0, 0, -1, 0, 0, 0, 1, 0, 0, -1, 0, 0, 0, 1, 0, 0, -1, 0, 0, 0, 1, 0, 0, -1, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0 COMMENTS This sequence is called C(n) in a comment on A234044, where it appears, together with five others called a,b,c, and A, B, in a formula for 2*exp(2*Pi*n*I/7). See A234044 for details and the example for n = 4. LINKS Index entries for linear recurrences with constant coefficients, signature (-1,-1,-1,-1,-1,-1). FORMULA G.f.: x^2*(1 - x^3)/(1 - x^7). a(n+7) = a(n), n >= 0, with a(k) = 0 for k = 0, 1, 3, 4, 6 and a(2) = -a(5) = 1. a(n) = (n+2)^6 mod 7 - (n+5)^6 mod 7. - Paolo P. Lava, Feb 28 2014 From Wesley Ivan Hurt, Jul 18 2016: (Start) a(n) = floor((1+n)/7) - floor((2+n)/7) - floor((4+n)/7) + floor((5+n)/7). a(n) + a(n-1) + a(n-2) + a(n-3) + a(n-4) + a(n-5) + a(n-6) for n>5. (End) MAPLE P:=proc(q) local n; for n from 0 to q do print(((n+2)^6 mod 7)-((n+5)^6 mod 7)); od; end: P(100); # Paolo P. Lava, Feb 28 2014 seq(op([0, 0, 1, 0, 0, -1, 0]), n=0..20); # Wesley Ivan Hurt, Jul 18 2016 MATHEMATICA PadRight[{}, 100, {0, 0, 1, 0, 0, -1, 0}] (* Wesley Ivan Hurt, Jul 18 2016 *) PROG (PARI) a(n)=[0, 0, 1, 0, 0, -1, 0][n%7+1] \\ Charles R Greathouse IV, Jul 13 2016 (MAGMA) &cat [[0, 0, 1, 0, 0, -1, 0]^^20]; // Wesley Ivan Hurt, Jul 18 2016 CROSSREFS Cf. A234044, A234045, A234046, A238468, A238469. Sequence in context: A099395 A182581 A288203 * A286748 A289001 A171588 Adjacent sequences:  A238467 A238468 A238469 * A238471 A238472 A238473 KEYWORD sign,easy AUTHOR Wolfdieter Lang, Feb 27 2014 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 15 20:24 EDT 2019. Contains 325056 sequences. (Running on oeis4.)