Duplicate of A067913.

Terms

a(0) =1a(1) =28a(2) =30a(3) =52a(4) =231a(5) =277a(6) =523a(7) =2278a(8) =22749a(9) =48854a(10) =371305a(11) =1447522a(12) =1726931a(13) =1947729