cp's OEIS Frontend

A111527 Inverse of A111526. Row sums have general term C(n,floor(n/2))*(cos(Pi*n/2) + sin(Pi*n/2)).

%I A111527 #7 Apr 11 2021 04:19:32
%S A111527 1,0,1,-3,0,1,0,-4,0,1,10,0,-5,0,1,0,15,0,-6,0,1,-35,0,21,0,-7,0,1,0,
%T A111527 -56,0,28,0,-8,0,1,126,0,-84,0,36,0,-9,0,1,0,210,0,-120,0,45,0,-10,0,
%U A111527 1,-462,0,330,0,-165,0,55,0,-11,0,1,0,-792,0,495,0,-220,0,66,0,-12,0,1,1716,0,-1287,0,715,0,-286,0,78,0,-13,0,1
%N A111527 Inverse of A111526. Row sums have general term C(n,floor(n/2))*(cos(Pi*n/2) + sin(Pi*n/2)).
%C A111527 Inverse of a scaled Chebyshev triangle.
%F A111527 Riordan array (c^2(-x^2)(1+x^2c(-x^2))/sqrt(1+4x^2), x*c(-x^2)), c(x) the g.f. of A000108.
%e A111527 Triangle begins
%e A111527     1;
%e A111527     0,  1;
%e A111527    -3,  0,  1;
%e A111527     0, -4,  0,  1;
%e A111527    10,  0, -5,  0,  1;
%e A111527     0, 15,  0, -6,  0,  1;
%e A111527   -35,  0, 21,  0, -7,  0,  1;
%K A111527 easy,sign,tabl
%O A111527 0,4
%A A111527 _Paul Barry_, Aug 05 2005