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A130779 a(0)=a(1)=1, a(2)=2, a(n)=0 for n >= 3. 9
1, 1, 2, 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, 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, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,3
COMMENTS
Inverse binomial transform of A002522. - R. J. Mathar, Jun 13 2008
Multiplicative with a(2)=2, a(2^e)=0 if e>1, a(p^e)=0 for odd prime p if e>=1. Dirichlet g.f. 1+2^(1-s). - R. J. Mathar, Jun 28 2011
a(n-1) is the determinant of the symmetric n X n matrix M(i,j) = rad(gcd(i,j)) for 1 <= i, j <= n, where rad(n) is the largest squarefree number dividing n (A007947). - Amiram Eldar, Jul 19 2019
REFERENCES
J. Sándor and B. Crstici, Handbook of Number Theory II, Kluwer, 2004, p. 265.
LINKS
FORMULA
G.f.: 1+x+2x^2.
a(n) = A167666(n,0). - Philippe Deléham, Feb 18 2012
a(n) = n! mod 3. - Charles Kusniec, Jan 25 2020
MATHEMATICA
PadRight[{1, 1, 2}, 120, 0] (* Harvey P. Dale, May 02 2015 *)
LinearRecurrence[{1}, {1, 1, 2, 0}, 105] (* Ray Chandler, Jul 15 2015 *)
PROG
(PARI) a(n)=if(n<3, max(n, 1), 0) \\ Charles R Greathouse IV, Dec 21 2011
CROSSREFS
Sequence in context: A063665 A276306 A340851 * A130706 A000038 A335462
KEYWORD
nonn,mult,easy
AUTHOR
Paul Curtz, Jul 14 2007
STATUS
approved

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Last modified March 29 06:15 EDT 2024. Contains 371265 sequences. (Running on oeis4.)