0,4

See also A115150, the third diagonal of triangle A113647 (called Y(2,1)).

(1-4*x)*(2*c(2*x)-1)/(1+x) with c(x) g.f. of A000108 (Catalan).

a(n)= A113647(n, n-1), n>=2.

a(n)= b(n)-4*b(n-1) with b(n):=A062992(n), n>=2; a(0)=1, a(1)=-1.

15= a(3) = A062992(3) - 4*A062992(2) = 67 - 4*13.

Sequence in context: A110822 A001849 A115150 this_sequence A092317 A160075 A044347

Adjacent sequences: A115135 A115136 A115137 this_sequence A115139 A115140 A115141

sign,easy

Wolfdieter Lang (wolfdieter.lang_AT_physik_DOT_uni-karlsruhe_DOT_de), Jan 13 2006