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 A130779 a(0)=a(1)=1, a(2)=2, a(n)=0 for n >= 3. 8
 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 Index entries for linear recurrences with constant coefficients, signature (1). FORMULA G.f.: 1+x+2x^2. a(n) = (C((n+2)^2,n+4) mod 2) + (C((n+1)^2,n+3) mod 2) + 2*(C(n^2,n+2) mod 2). - Paolo P. Lava, Dec 19 2007 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 Cf. A002522, A007947, A130706, A167666. Sequence in context: A063665 A276306 A072507 * A130706 A000038 A335462 Adjacent sequences:  A130776 A130777 A130778 * A130780 A130781 A130782 KEYWORD nonn,mult,easy AUTHOR Paul Curtz, Jul 14 2007 STATUS approved

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Last modified September 27 19:04 EDT 2020. Contains 337388 sequences. (Running on oeis4.)