Self-convolution of A173610.

Terms

a(0) =1a(1) =2a(2) =5a(3) =12a(4) =32a(5) =86a(6) =226a(7) =588a(8) =1596a(9) =4372a(10) =12065a(11) =33344a(12) =91344a(13) =249584a(14) =677896a(15) =1836048a(16) =5039672a(17) =13877256a(18) =38405640a(19) =106482832a(20) =296373672a(21) =826270666a(22) =2307068226a(23) =6445895588a(24) =17963996648a(25) =50028938140a(26) =139149397474