0,1

Third Chebyshev polynomial second kind evaluated at 2^n.

Index entries for sequences related to Chebyshev polynomials.

G.f.: 4(1+4x)/(1-10x+16x^2).

U_3(x)=8x^3-4x so U_3(2^n)=8(2^n)^3-4(2^n)=8^(n+1)-2^(n+2).

with(orthopoly):seq(U(3, 2^i), i=0..24);

(PARI) a(n)=if(n<0, 0, 8^(n+1)-2^(n+2))

Sequence in context: A054751 A006592 A077122 this_sequence A101540 A026740 A130219

Adjacent sequences: A020537 A020538 A020539 this_sequence A020541 A020542 A020543

nonn

Simon Plouffe (plouffe(AT)math.uqam.ca)