a(n) = Pell(n)*A004016(n) for n >= 1, with a(0)=1, where A004016(n) is the number of integer solutions (x,y) to x^2 + x*y + y^2 = n.
A209446
a(n) = Pell(n)*A004016(n) for n >= 1, with a(0)=1, where A004016(n) is the number of integer solutions (x,y) to x^2 + x*y + y^2 = n.
Terms
- a(0) =1a(1) =6a(2) =0a(3) =30a(4) =72a(5) =0a(6) =0a(7) =2028a(8) =0a(9) =5910a(10) =0a(11) =0a(12) =83160a(13) =401532a(14) =0a(15) =0a(16) =2824992a(17) =0a(18) =0a(19) =79501308a(20) =0a(21) =463367580a(22) =0a(23) =0a(24) =0a(25) =7870428726a(26) =0a(27) =45872220270a(28) =221490672624a(29) =0
External references
- oeis: A209446