Number of distinct permutations generated by shuffling n cards with "clump size" <= 2.

Terms

a(0) =2a(1) =5a(2) =10a(3) =16a(4) =26a(5) =42a(6) =68a(7) =110a(8) =178a(9) =288a(10) =466a(11) =754a(12) =1220a(13) =1974a(14) =3194a(15) =5168a(16) =8362a(17) =13530a(18) =21892a(19) =35422a(20) =57314a(21) =92736a(22) =150050a(23) =242786a(24) =392836a(25) =635622a(26) =1028458a(27) =1664080a(28) =2692538a(29) =4356618