0,3

First differences are A117451. Second differences are A117452.

a(n)=2a(n-1)-a(n-2)+a(n-5)-2a(n-6)+a(n-7); a(n)=sum{k=0..n, C(n-k,L(k/5))}, where L(j/p) is the Legendre symbol of j and p; a(n)=(1/10-sqrt(5)/50)*cos(4*pi*n/5+2*pi/5)+sqrt(1/10+sqrt(5)/50)*sin(4*pi*n/5+2*pi/5) -(1/10+sqrt(5)/50)*cos(2*pi*n/5+pi/5)+sqrt(1/10-sqrt(5)/50)*sin(2*pi*n/5+pi/5) +(n^2+n+3)/5.

Sequence in context: A038197 A023546 A084913 this_sequence A132381 A073152 A051061

Adjacent sequences: A117447 A117448 A117449 this_sequence A117451 A117452 A117453

easy,nonn

Paul Barry (pbarry(AT)wit.ie), Mar 16 2006