Number of compositions of 7*n-4 into parts 1 and 7.

Terms

a(0) =1a(1) =5a(2) =22a(3) =105a(4) =518a(5) =2555a(6) =12565a(7) =61748a(8) =303470a(9) =1491567a(10) =7331205a(11) =36033501a(12) =177107406a(13) =870496256a(14) =4278555247a(15) =21029425081a(16) =103361226864a(17) =508028305120