Number of compositions of n with runs-resistance 2.

Terms

a(0) =0a(1) =0a(2) =2a(3) =3a(4) =6a(5) =15a(6) =22a(7) =41a(8) =72a(9) =129a(10) =213a(11) =395a(12) =660a(13) =1173a(14) =2031a(15) =3582a(16) =6188a(17) =10927a(18) =18977a(19) =33333a(20) =58153a(21) =101954a(22) =178044a(23) =312080a(24) =545475a(25) =955317a(26) =1670990a(27) =2925711a(28) =5118558a(29) =8960938