%I A091526
%S A091526 1,1,1,2,9,34,130,496,1897,7274,27966,107788,416394,1611908,6251596,
%T A091526 24287212,94499689,368202778,1436458486,5610483532,21936442894,
%U A091526 85852554748,336300861436,1318441228432,5172792817834,20309402206084
%V A091526 1,-1,1,2,9,34,130,496,1897,7274,27966,107788,416394,1611908,6251596,24287212,
               94499689,
%W A091526 368202778,1436458486,5610483532,21936442894,85852554748,336300861436,
               1318441228432,
%X A091526 5172792817834,20309402206084
%N A091526 Coefficient of x^n in 1/((1+x)(1-x)^(n-1)).
%C A091526 Number of positive terms in expansion of (x_1+x_2+...+x_{n-1}-x_n)^(n+1). 
               - Sergio Falcon (sfalcon(AT)dma.ulpgc.es), Feb 08 2007
%o A091526 (PARI) a(n)=sum(i=0,n,binomial(n+i-2,i)*(-1)^(n-i))
%Y A091526 Sequence in context: A120989 A010763 A077234 this_sequence A150937 A150938 
               A151307
%Y A091526 Adjacent sequences: A091523 A091524 A091525 this_sequence A091527 A091528 
               A091529
%K A091526 sign
%O A091526 0,4
%A A091526 Michael Somos, Jan 18 2004