A070464 a(n) = n^2 mod 42.

0, 1, 4, 9, 16, 25, 36, 7, 22, 39, 16, 37, 18, 1, 28, 15, 4, 37, 30, 25, 22, 21, 22, 25, 30, 37, 4, 15, 28, 1, 18, 37, 16, 39, 22, 7, 36, 25, 16, 9, 4, 1, 0, 1, 4, 9, 16, 25, 36, 7, 22, 39, 16, 37, 18, 1, 28, 15, 4, 37, 30, 25, 22, 21, 22, 25, 30, 37, 4, 15, 28, 1, 18, 37, 16, 39

Offset: 0

Author

N. J. A. Sloane, May 12 2002

Keywords

• nonn
• easy

Links

• Vincenzo Librandi, Table of n, a(n) for n = 0..1400
• 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, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1).

Crossrefs

Cf. A070461, A070462, A070463.

Programs

Magma

[n^2 mod 42: n in [0..80]]; // Vincenzo Librandi, Apr 27 2011

Mathematica

Table[Mod[n^2,42],{n,0,200}] (* Vladimir Joseph Stephan Orlovsky, Apr 27 2011 *)
PowerMod[Range[0,80],2,42] (* Harvey P. Dale, Mar 13 2019 *)

PARI

a(n)=n^2%42 \\ Charles R Greathouse IV, Apr 06 2016

Formula

a(n) = a(n-42). - G. C. Greubel, Mar 25 2016