What is the value of `a_(7)` if `a_(n)=1+(-1)^(n)`?

What is the value of a_(3) if a_(n)=|(n)/(2)|+|(n+1)/(2)|?

If alpha and beta are roots of the equation x^(2)-3x+1=0 and a_(n)=alpha^(n)+beta^(n)-1 then find the value of (a_(5)-a_(1))/(a_(3)-a_(1))

If a_(n)=(1)/(n+1)+1 then find the vaue of a_(1)+a_(3)+a_(5)

(1+x)(sum_(r=0)^(n)nC_(r)x^(r))+(1+x^(2))(sum_(r=0)^(n-1)(n-1)C_(r)x^(r))+...(1+x^(n))(sum_(r=0)^(1)1C_(r)x^(r))=a_(0)+a_(1)x+, then the value of (a_(1))/(a_(n)+1)+(a_(1))/(a_(n))+(a_(2))/(a_(n-1))+......+(a_(n+1))/(a_(0)) is equal to

Given that (1+x+x^(2))^(n)=a_(0)+a_(1)x+a_(2)x^(2)+......+a_(2n)x^(2n) , find the values of a_(0)^(2)-a_(1)^(2)+a_(2)^(2)-a_(3)^(2)+....+a_(2n)^(2)

If (1-x)^(-n)=a_(0)+a_(1)x+a_(2)x^(2)+a_(3)x^(3)+... find the value of,a_(0)+a_(1)+a_(2)+......+a_(n)

Let the sequence a_(1),a_(2),a_(3),...,a_(n) from an A.P.Then the value of a_(1)^(2)-a_(2)^(2)+a_(3)^(2)-...+a_(2n-1)^(2)-a_(2n)^(2) is (2n)/(n-1)(a_(2n)^(2)-a_(1)^(2))(b)(n)/(2n-1)(a_(1)^(2)-a_(2n)^(2))(n)/(n+1)(a_(1)^(2)-a_(2n)^(2))(d)(n)/(n-1)(a_(1)^(2)+a_(2n)^(2))

If a_(1)=2 and a_(n)-a_(n-1)=2n(n>=2), find the value of a_(1)+a_(2)+a_(3)+....+a_(20)