Number of sphenic twins up to 10^n.

Terms

a(0) =0a(1) =0a(2) =11a(3) =337a(4) =4206a(5) =43330a(6) =417479a(7) =3917508a(8) =36358375a(9) =336046778a(10) =3105465308a(11) =28739218426