Relates row sums of Pascal's triangle to expansion of cos(x)/exp(x).

Terms

a(0) =1a(1) =4a(2) =9a(3) =16a(4) =26a(5) =44a(6) =84a(7) =176a(8) =376a(9) =784a(10) =1584a(11) =3136a(12) =6176a(13) =12224a(14) =24384a(15) =48896a(16) =98176a(17) =196864a(18) =393984a(19) =787456a(20) =1573376a(21) =3144704a(22) =6288384a(23) =12578816a(24) =25163776a(25) =50335744a(26) =100675584a(27) =201342976a(28) =402661376a(29) =805289984