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A027414
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G.f. for Moebius transform is x * (1 + x) / (1 + x^4).
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1
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1, 2, 1, 2, 0, 1, 1, 2, 2, 2, 1, 1, 0, 1, 0, 2, 2, 3, 1, 2, 0, 1, 1, 1, 1, 2, 2, 1, 0, 0, 1, 2, 2, 4, 0, 3, 0, 1, 0, 2, 2, 0, 1, 1, 0, 1, 1, 1, 2, 4, 2, 2, 0, 2, 0, 1, 2, 2, 1, 0, 0, 1, 1, 2, 0, 2, 1, 4, 0, 0, 1, 3, 2, 2, 1, 1, 0, 0, 1, 2, 3, 4, 1, 0, 0, 1, 0, 1, 2, 2, 0, 1, 0, 1, 0, 1, 2, 3, 3, 4, 0, 2, 1, 2, 0
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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LINKS
| N. J. A. Sloane, Transforms
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FORMULA
| Moebius transform is period 8 sequence [1, 1, 0, 0, -1, -1, 0, 0, ...]. - Michael Somos, Sep 20 2005
G.f.: Sum_{k>0} x^k * (1 + x^k) / (1 + x^(4*k)). - Michael Somos, Sep 20 2005
a(8*n + 5) = 0. a(8*n + 3) = A033761(n). - Michael Somos, Nov 16 2011
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EXAMPLE
| x + 2*x^2 + x^3 + 2*x^4 + x^6 + x^7 + 2*x^8 + 2*x^9 + 2*x^10 + x^11 + x^12 + ...
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MATHEMATICA
| a[ n_] := If[ n < 1, 0, Sum[ {1, 1, 0, 0, -1, -1, 0, 0} [[ Mod[d, 8, 1]]], {d, Divisors @ n}]] (* Michael Somos, Nov 16 2011 *)
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PROG
| (PARI) {a(n) = if( n<1, 0, sumdiv( n, d, kronecker( -4, (d-1)%8\2 + 1)))} /* Michael Somos, Sep 20 2005 */
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CROSSREFS
| Sequence in context: A171099 A127173 A035160 * A140083 A057985 A135387
Adjacent sequences: A027411 A027412 A027413 * A027415 A027416 A027417
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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