Fermat coefficients.

Terms

a(0) =1a(1) =7a(2) =25a(3) =66a(4) =143a(5) =273a(6) =476a(7) =775a(8) =1197a(9) =1771a(10) =2530a(11) =3510a(12) =4750a(13) =6293a(14) =8184a(15) =10472a(16) =13209a(17) =16450a(18) =20254a(19) =24682a(20) =29799a(21) =35673a(22) =42375a(23) =49980a(24) =58565a(25) =68211a(26) =79002a(27) =91025a(28) =104371a(29) =119133