Alternating sum of the first n Fibonacci numbers.

Terms

a(0) =0a(1) =-1a(2) =0a(3) =-2a(4) =1a(5) =-4a(6) =4a(7) =-9a(8) =12a(9) =-22a(10) =33a(11) =-56a(12) =88a(13) =-145a(14) =232a(15) =-378a(16) =609a(17) =-988a(18) =1596a(19) =-2585a(20) =4180a(21) =-6766a(22) =10945a(23) =-17712a(24) =28656a(25) =-46369a(26) =75024a(27) =-121394a(28) =196417a(29) =-317812