An inverse Chebyshev transform of the Jacobsthal numbers.

Terms

a(0) =0a(1) =1a(2) =1a(3) =6a(4) =9a(5) =36a(6) =66a(7) =218a(8) =449a(9) =1332a(10) =2946a(11) =8196a(12) =18954a(13) =50688a(14) =120576a(15) =314586a(16) =761889a(17) =1957092a(18) =4794426a(19) =12194828a(20) =30093854a(21) =76067256a(22) =188595276a(23) =474810276a(24) =1180734234a(25) =2965094536a(26) =7387570516a(27) =18521858088a(28) =46203981924a(29) =115721310552