The maid is defined by the recurrence relation:
FN= FN1 +
FN2,
Where F1 = 1 and F2 = 1.
Hence the first 12 terms will be:
F1 = 1
F2 = 1
F3 = 2
F4 = 3
F5 = 5
F6 = 8
F7 = 13
F8 = 21
F9 = 34
F10 = 55
F11 = 89
F12 = 144.
The 12th term, F12, is the first term to contain three digits.
What is the first term in the Fibonacci sequence to contain 1000 digits?
Http://projecteuler.net/problem=25
Import Java. math. biginteger; public class verybiginteger {public static void main (string ARGs []) {biginteger [] Bi = new biginteger [40000000]; bi [0] = new biginteger ("1"); Bi [1] = new biginteger ("1"); For (INT I = 2; I <bi. length; I ++) {Bi [I] = Bi [I-1]. add (Bi [I-2]); If ("" + bi [I]). length ()> = 1000) {system. out. println ("I =" + I); system. out. println ("Bi [I] =" + bi [I]); break ;}}}}
I = 4781.
Bi [I] = 1070066266382758936764980584457396885083683896632151665013235203375314520604694040621889147582489792657804694888177591957484336466672569959512996030461262748092482186144069433051234774442750273781753087579391666192149259186759553966422837148943113074699503439547001985432609723067290192870526447243726117715821825548491120525013201478612965931381792235559657452039506137551467837543229119602129934048260706175397706847068202895486902666185435124521900369480641357447470911707619766945691070098024393439617474103736912503231365532164773697023167755051595173518460579954919410967778373229665796581646513903488154256310184224190259846088000110186255550245493937113651657039447629584714548523425950428582425306083544435428212611008992863795048006894330309773217834864543113205765659868456288616808718693835297350643986297640660000723562917905207051164077614812491885830945940566688339109350944456576357666151619317753792891661581327159616877487983821820492520348473874384736771934512787029218636250627816