a(n) = 3rd elementary symmetric function of the first n+2 odd positive integers.

Terms

a(0) =15a(1) =176a(2) =950a(3) =3480a(4) =10045a(5) =24640a(6) =53676a(7) =106800a(8) =197835a(9) =345840a(10) =576290a(11) =922376a(12) =1426425a(13) =2141440a(14) =3132760a(15) =4479840a(16) =6278151a(17) =8641200a(18) =11702670a(19) =15618680a(20) =20570165a(21) =26765376a(22) =34442500a(23) =43872400a(24) =55361475a(25) =69254640a(26) =85938426a(27) =105844200a(28) =129451505