The Euclid tree with root 1 encoded by semiprimes, read across levels.

Terms

a(0) =4a(1) =-6a(2) =6a(3) =-21a(4) =35a(5) =-35a(6) =21a(7) =-10a(8) =221a(9) =-77a(10) =55a(11) =-55a(12) =77a(13) =-221a(14) =10a(15) =-33a(16) =46513a(17) =-493a(18) =377a(19) =-119a(20) =187a(21) =-1333a(22) =559a(23) =-559a(24) =1333a(25) =-187a(26) =119a(27) =-377a(28) =493a(29) =-46513