Self-convolution cube of A108447.

Terms

a(0) =1a(1) =3a(2) =15a(3) =85a(4) =519a(5) =3330a(6) =22135a(7) =151089a(8) =1052805a(9) =7458236a(10) =53554548a(11) =388913046a(12) =2851368587a(13) =21076979445a(14) =156907929177