Number of compositions of n such that the maximal distance between two identical parts equals one.

Terms

a(0) =0a(1) =0a(2) =1a(3) =0a(4) =3a(5) =4a(6) =5a(7) =12a(8) =21a(9) =36a(10) =43a(11) =88a(12) =133a(13) =222a(14) =331a(15) =450a(16) =753a(17) =1120a(18) =1703a(19) =2508a(20) =3753a(21) =5010a(22) =7807a(23) =11020a(24) =16243a(25) =22974a(26) =33277a(27) =46764a(28) =63639a(29) =91822