The number of compositions of n with no more than 3 consecutive identical parts (summands).

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =7a(5) =15a(6) =29a(7) =57a(8) =111a(9) =218a(10) =429a(11) =841a(12) =1651a(13) =3239a(14) =6355a(15) =12473a(16) =24475a(17) =48029a(18) =94249a(19) =184946a(20) =362932a(21) =712194a(22) =1397569a(23) =2742507a(24) =5381729a(25) =10560797a(26) =20723884a(27) =40667338a(28) =79803197a(29) =156601100