a(n) = a(n-1) - 49*a(n-2), a(0)=1, a(1)=7.

Terms

a(0) =1a(1) =7a(2) =-42a(3) =-385a(4) =1673a(5) =20538a(6) =-61439a(7) =-1067801a(8) =1942710a(9) =54264959a(10) =-40927831a(11) =-2699910822a(12) =-694447103a(13) =131601183175a(14) =165629091222