The sum of the semiperimeters of the bargraphs of area n (n>=1).

Terms

a(0) =2a(1) =6a(2) =16a(3) =39a(4) =92a(5) =211a(6) =476a(7) =1059a(8) =2332a(9) =5091a(10) =11036a(11) =23779a(12) =50972a(13) =108771a(14) =231196a(15) =489699a(16) =1034012a(17) =2177251a(18) =4572956a(19) =9582819a(20) =20039452a(21) =41826531a(22) =87148316a(23) =181287139a(24) =376555292a(25) =781072611a(26) =1618069276a(27) =3347986659a(28) =6919669532a(29) =14286731491