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A183893
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Real part of a Gaussian integer sequence with a Gaussian integer Somos-4 Hankel transform.
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4
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1, 1, -1, -1, 9, 9, -73, -73, 697, 697, -7161, -7161, 77457, 77457, -868881, -868881, 10016241, 10016241, -117935473, -117935473, 1412307481, 1412307481, -17148100569, -17148100569, 210619695913, 210619695913, -2612194773481, -2612194773481, 32668519882017, 32668519882017, -411515480555553
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OFFSET
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0,5
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COMMENTS
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LINKS
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FORMULA
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a(n) = Re(Sum{k=0..n, C(floor((n+k)/2),k)*I^k*A000108(k)}), I=sqrt(-1).
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MATHEMATICA
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Table[Re[Sum[I^k*Binomial[2*k, k]*Binomial[Floor[(n + k)/2], k]/(k + 1), {k, 0, n}]], {n, 0, 50}] (* G. C. Greubel, Feb 21 2018 *)
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PROG
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(PARI) for(n=0, 50, print1(real(sum(k=0, n, I^k*binomial(2*k, k)* binomial( floor((n+k)/2), k)/(k+1) )), ", ")) \\ G. C. Greubel, Feb 21 2018
(Magma) [Round(Real((&+[(Sqrt(-1))^k*Binomial(2*k, k)*Binomial( Floor((n+k)/2), k)/(k+1): k in [0..n]]))): n in [0..30]]; // G. C. Greubel, Feb 21 2018
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CROSSREFS
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KEYWORD
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sign
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AUTHOR
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STATUS
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approved
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