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%I #8 Jun 25 2019 01:06:05
%S 1,2,0,-8,-32,-256,0,16384,262144,8388608,0,-8589934592,-549755813888,
%T -70368744177664,0,1152921504606846976,295147905179352825856,
%U 151115727451828646838272,0,-39614081257132168796771975168
%N Hankel transform of a transform of the central binomial coefficients A001405.
%C Hankel transform of A134184.
%F a(n) = ((1/2 - 1/sqrt(2))*cos(3*Pi*n/4) + (1/2 + 1/sqrt(2))*cos(Pi*n/4))*2^ceiling(binomial(n+1,2)/2).
%Y Cf. A001405, A134184.
%K easy,sign
%O 0,2
%A _Paul Barry_, Oct 11 2007