A Jacobsthal trisection.

Terms

a(0) =1a(1) =0a(2) =8a(3) =56a(4) =456a(5) =3640a(6) =29128a(7) =233016a(8) =1864136a(9) =14913080a(10) =119304648a(11) =954437176a(12) =7635497416a(13) =61083979320a(14) =488671834568