a(n) = number of subsets S of {1,2,...,n} having more than 1 element such that (difference between least two elements of S) = difference between greatest two elements of S.
A357282
a(n) = number of subsets S of {1,2,...,n} having more than 1 element such that (difference between least two elements of S) = difference between greatest two elements of S.
Terms
- a(0) =0a(1) =0a(2) =1a(3) =4a(4) =9a(5) =18a(6) =33a(7) =60a(8) =109a(9) =202a(10) =381a(11) =732a(12) =1425a(13) =2802a(14) =5545a(15) =11020a(16) =21957a(17) =43818a(18) =87525a(19) =174924a(20) =349705a(21) =699250a(22) =1398321a(23) =2796444a(24) =5592669a(25) =11185098a(26) =22369933a(27) =44739580a(28) =89478849a(29) =178957362
External references
- oeis: A357282