a(n) = a(n-2) - 2a(n-3) + a(n-4) for n>3, with a(0)=2, a(1)=0, a(2)=1, a(3)=-1, a sequence related to Pellian numbers.
A292521
a(n) = a(n-2) - 2a(n-3) + a(n-4) for n>3, with a(0)=2, a(1)=0, a(2)=1, a(3)=-1, a sequence related to Pellian numbers.
Terms
- a(0) =2a(1) =0a(2) =1a(3) =-1a(4) =3a(5) =-3a(6) =6a(7) =-10a(8) =15a(9) =-25a(10) =41a(11) =-65a(12) =106a(13) =-172a(14) =277a(15) =-449a(16) =727a(17) =-1175a(18) =1902a(19) =-3078a(20) =4979a(21) =-8057a(22) =13037a(23) =-21093a(24) =34130a(25) =-55224a(26) =89353a(27) =-144577a(28) =233931a(29) =-378507
External references
- oeis: A292521