Number of compositions (ordered partitions) of n into parts 1, 2, and 5.

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =5a(5) =9a(6) =15a(7) =26a(8) =44a(9) =75a(10) =128a(11) =218a(12) =372a(13) =634a(14) =1081a(15) =1843a(16) =3142a(17) =5357a(18) =9133a(19) =15571a(20) =26547a(21) =45260a(22) =77164a(23) =131557a(24) =224292a(25) =382396a(26) =651948a(27) =1111508a(28) =1895013a(29) =3230813