Self-convolution of sequence A001402.

Terms

a(0) =1a(1) =2a(2) =5a(3) =10a(4) =20a(5) =36a(6) =65a(7) =108a(8) =179a(9) =284a(10) =445a(11) =676a(12) =1017a(13) =1492a(14) =2168a(15) =3094a(16) =4372a(17) =6088a(18) =8406a(19) =11462a(20) =15509a(21) =20770a(22) =27614a(23) =36390a(24) =47646a(25) =61898a(26) =79939a(27) =102538a(28) =130808a(29) =165864