THE rabbits on the island of Hermaphra each produce a litter of offspring each year, and become more prolific with age. The colony originated in the year dot, with just one newborn individual. The following year she/he/it produced just one offspring. In the year dot +2 the original colonnist produced two offspring, and the previous year’s newborn produced one. In each subsequent year, each individual gave birth to a litter equal in number to her age in years.
In which year did the population reach one billion?
A £10 book token will be awarded to the sender of the first correct answer opened on Thursday 18 May. The Editor’s decision is final. Please send entries to Enigma 818, Â鶹´«Ã½, King’s Reach Tower, Stamford Street, London SE99 0BB. The winner of Enigma 812 was Andrew Plant of Lymingham.
Answer to Enigma 812
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Upon my word! 27
