Form array in which n-th row is obtained by expanding (1+x+x^2)^n and taking the 3rd column from the center.

A014532

Form array in which n-th row is obtained by expanding (1+x+x^2)^n and taking the 3rd column from the center.

Terms

    a(0) =1a(1) =4a(2) =15a(3) =50a(4) =161a(5) =504a(6) =1554a(7) =4740a(8) =14355a(9) =43252a(10) =129844a(11) =388752a(12) =1161615a(13) =3465840a(14) =10329336a(15) =30759120a(16) =91538523a(17) =272290140a(18) =809676735a(19) =2407049106a(20) =7154586747a(21) =21263575256a(22) =63191778950a(23) =187790510700a(24) =558069593445

External references