Number of compositions of 5*n-4 into parts 2 and 5.

Terms

a(0) =0a(1) =1a(2) =4a(3) =11a(4) =29a(5) =81a(6) =235a(7) =685a(8) =1986a(9) =5739a(10) =16577a(11) =47904a(12) =138472a(13) =400285a(14) =1157071a(15) =3344567a(16) =9667590a(17) =27944604a(18) =80775310a(19) =233485250a(20) =674901117a(21) =1950836005a(22) =5638990526a(23) =16299788815a(24) =47115369056a(25) =136189372297a(26) =393662311506