This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A134185 #8 Jun 25 2019 01:06:05 %S A134185 1,2,0,-8,-32,-256,0,16384,262144,8388608,0,-8589934592,-549755813888, %T A134185 -70368744177664,0,1152921504606846976,295147905179352825856, %U A134185 151115727451828646838272,0,-39614081257132168796771975168 %N A134185 Hankel transform of a transform of the central binomial coefficients A001405. %C A134185 Hankel transform of A134184. %F A134185 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 A134185 Cf. A001405, A134184. %K A134185 easy,sign %O A134185 0,2 %A A134185 _Paul Barry_, Oct 11 2007