Form array in which n-th row is obtained by expanding (1+x+x^2)^n and taking the 2nd column from the center.

A014531

Form array in which n-th row is obtained by expanding (1+x+x^2)^n and taking the 2nd column from the center.

Terms

    a(0) =1a(1) =3a(2) =10a(3) =30a(4) =90a(5) =266a(6) =784a(7) =2304a(8) =6765a(9) =19855a(10) =58278a(11) =171106a(12) =502593a(13) =1477035a(14) =4343160a(15) =12778152a(16) =37616427a(17) =110797569a(18) =326527350a(19) =962803170a(20) =2840372304a(21) =8383467708a(22) =24755608584a(23) =73133433800a(24) =216143407675a(25) =639062383401

External references