Number of subsets of {1..n} with all different first differences of elements.

Terms

a(0) =1a(1) =2a(2) =4a(3) =7a(4) =13a(5) =22a(6) =36a(7) =61a(8) =99a(9) =156a(10) =240a(11) =381a(12) =587a(13) =894a(14) =1334a(15) =1967a(16) =2951a(17) =4370a(18) =6406a(19) =9293a(20) =13357a(21) =18976a(22) =27346a(23) =39013a(24) =55437a(25) =78154a(26) =109632a(27) =152415a(28) =210801a(29) =293502