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A070447
a(n) = n^2 mod 25.
1
0, 1, 4, 9, 16, 0, 11, 24, 14, 6, 0, 21, 19, 19, 21, 0, 6, 14, 24, 11, 0, 16, 9, 4, 1, 0, 1, 4, 9, 16, 0, 11, 24, 14, 6, 0, 21, 19, 19, 21, 0, 6, 14, 24, 11, 0, 16, 9, 4, 1, 0, 1, 4, 9, 16, 0, 11, 24, 14, 6, 0, 21, 19, 19, 21, 0, 6, 14, 24, 11, 0, 16, 9, 4, 1, 0, 1, 4, 9, 16, 0, 11, 24, 14, 6
OFFSET
0,3
LINKS
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, 1).
FORMULA
G.f.: (x + 4*x^2 + 9*x^3 + 16*x^4 + 11*x^6 + 24*x^7 + 14*x^8 + 6*x^9 + 21*x^11 + 19*x^12 + 19*x^13 + 21*x^14 + 6*x^16 + 14*x^17 + 24*x^18 + 11*x^19 + 16*x^21 + 9*x^22 + 4*x^23 + x^24) / (1 - x^25). - Vincenzo Librandi, Dec 17 2014
a(n) = (n + 25h); a(n) = 0 if n == 0 (mod 5). Also, a(r) = a(s) if r+s == 0 (mod 25). - Vincenzo Librandi, Dec 18 2014
MATHEMATICA
Table[Mod[n^2, 25], {n, 0, 200}] (* Vladimir Joseph Stephan Orlovsky, Apr 23 2011 *)
PROG
(Magma) [n^2 mod 25: n in [0..100]]; // Vincenzo Librandi, Dec 18 2014
(PARI) a(n)=n^2%25 \\ Charles R Greathouse IV, Apr 06 2016
CROSSREFS
Sequence in context: A356928 A357807 A337568 * A106548 A106546 A276191
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, May 12 2002
STATUS
approved