A070462 a(n) = n^2 mod 40.

0, 1, 4, 9, 16, 25, 36, 9, 24, 1, 20, 1, 24, 9, 36, 25, 16, 9, 4, 1, 0, 1, 4, 9, 16, 25, 36, 9, 24, 1, 20, 1, 24, 9, 36, 25, 16, 9, 4, 1, 0, 1, 4, 9, 16, 25, 36, 9, 24, 1, 20, 1, 24, 9, 36, 25, 16, 9, 4, 1, 0, 1, 4, 9, 16, 25, 36, 9, 24, 1, 20, 1, 24, 9, 36, 25, 16, 9, 4, 1, 0, 1, 4, 9, 16

Offset

0,3

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, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1).

Formula

a(n) = a(n-20). - G. C. Greubel, Mar 25 2016

Mathematica

Table[Mod[n^2, 40], {n, 0, 200}] (* Vladimir Joseph Stephan Orlovsky, Apr 27 2011 *)
PowerMod[Range[0, 90], 2, 40] (* Harvey P. Dale, Oct 20 2013 *)

Prog

(PARI) a(n)=n^2%40 \\ Charles R Greathouse IV, Apr 06 2016

Crossrefs

Cf. A070456, A070457.

Sequence in context: A070465 A070464 A070463 * A070461 A070460 A070459

Adjacent sequences: A070459 A070460 A070461 * A070463 A070464 A070465

Keyword

nonn,easy

Author

N. J. A. Sloane, May 12 2002

Status

approved