Number of partitions of an n-set without blocks of size 7.

Terms

a(0) =1a(1) =1a(2) =2a(3) =5a(4) =15a(5) =52a(6) =203a(7) =876a(8) =4132a(9) =21075a(10) =115375a(11) =673620a(12) =4172413a(13) =27296089a(14) =187891174a(15) =1356343385a(16) =10238632307a(17) =80615222404a(18) =660560758879