Sum of Fibonacci numbers between F(-n)....F(n), inclusive.

Terms

a(0) =0a(1) =2a(2) =2a(3) =6a(4) =6a(5) =16a(6) =16a(7) =42a(8) =42a(9) =110a(10) =110a(11) =288a(12) =288a(13) =754a(14) =754a(15) =1974a(16) =1974a(17) =5168a(18) =5168a(19) =13530a(20) =13530a(21) =35422a(22) =35422a(23) =92736a(24) =92736a(25) =242786a(26) =242786a(27) =635622a(28) =635622a(29) =1664080