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 A260192 Kronecker symbol(-6 / 2*n + 7). 4
 1, 0, 1, -1, 0, -1, -1, 0, -1, 1, 0, 1, 1, 0, 1, -1, 0, -1, -1, 0, -1, 1, 0, 1, 1, 0, 1, -1, 0, -1, -1, 0, -1, 1, 0, 1, 1, 0, 1, -1, 0, -1, -1, 0, -1, 1, 0, 1, 1, 0, 1, -1, 0, -1, -1, 0, -1, 1, 0, 1, 1, 0, 1, -1, 0, -1, -1, 0, -1, 1, 0, 1, 1, 0, 1, -1, 0, -1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0 LINKS G. C. Greubel, Table of n, a(n) for n = 0..1000 Index entries for linear recurrences with constant coefficients, signature (0,1,0,-1). FORMULA Euler transform of length 12 sequence [ 0, 1, -1, -1, 0, -1, 0, 0, 0, 0, 0, 1]. G.f.: (1 - x^3) / (1 - x^2 + x^4). a(n) = -(-1)^n * a(n+3) = -a(n+6) = a(-1-n) = a(n+2) - a(n+4) for all n in Z. a(n) = = (-1)^n * A260190(n) = A117441(n+1) = A109017(2*n + 7). a(2*n) = A010892(n). a(2*n + 1) = A128834(n). a(3*n + 1) = 0. a(3*n) = a(3*n + 2) = A087960(n). EXAMPLE G.f. = 1 + x^2 - x^3 - x^5 - x^6 - x^8 + x^9 + x^11 + x^12 + x^14 - x^15 + ... MATHEMATICA a[ n_] := KroneckerSymbol[ -6, 2 n + 7]; LinearRecurrence[{0, 1, 0, -1}, {1, 0, 1, -1}, 50] (* G. C. Greubel, Jan 15 2018 *) PROG (PARI) {a(n) = kronecker( -6, 2*n + 7)}; (PARI) {a(n) = (-1)^(n\6 + n) * [1, 0, 1][n%3 + 1]}; (PARI) {a(n) = if( n<0, n=-1-n); polcoeff( (1 - x^3) / (1 - x^2 + x^4) + x * O(x^n), n)}; (MAGMA) I:=[1, 0, 1, -1]; [n le 4 select I[n] else Self(n-2) - Self(n-4): n in [1..30]]; // G. C. Greubel, Jan 15 2018 CROSSREFS Cf. A087960, A109017, A117441, A128834, A260190. Sequence in context: A305385 A204418 A260190 * A057078 A127245 A175192 Adjacent sequences:  A260189 A260190 A260191 * A260193 A260194 A260195 KEYWORD sign,easy AUTHOR Michael Somos, Jul 18 2015 STATUS approved

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Last modified December 11 18:34 EST 2019. Contains 329925 sequences. (Running on oeis4.)