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 A127511 #13 Jan 02 2025 11:05:08
%S A127511 1,-2,-4,0,-16,32,-64,0,0,512,-1024,0,-4096,8192,16384,0,-65536,0,
%T A127511 -262144,0,1048576,2097152,-4194304,0,0,33554432,0,0,-268435456,
%U A127511 -536870912,-1073741824,0,4294967296,8589934592,17179869184,0,-68719476736,137438953472,274877906944,0,-1099511627776
%N A127511 a(n) = mu(n) * 2^(n-1).
%C A127511 Row sums of A127512.
%C A127511 Appears to be the determinant of A156734 where the element in the lower right corner has been swapped with the element in the upper right corner. - _Mats Granvik_, Feb 14 2009
%F A127511 a(n)=A008683(n)*A000079(n-1). - _R. J. Mathar_, May 19 2007
%e A127511 a(5) = (-1)*16 = -16 since mu(5) = -1 and 2^4 = 16.
%p A127511 A127511 := proc(n) 2^(n-1)*numtheory[mobius](n) ; end: for n from 1 to 50 do printf("%d, ",A127511(n)) ; od ; # _R. J. Mathar_, May 19 2007
%t A127511 Array[MoebiusMu[#]*2^(#-1)&,41] (* _James C. McMahon_, Jan 02 2025 *)
%Y A127511 Cf. A008683, A127512.
%K A127511 sign,easy
%O A127511 1,2
%A A127511 _Gary W. Adamson_, Jan 17 2007
%E A127511 More terms from _R. J. Mathar_, May 19 2007