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Enigma Number 1651

By Richard England

15 June 2011

Four-digit numbers

I have found a 3-digit perfect square, a 3-digit perfect cube and a 4-digit triangular number that between them use 10 different digits, with no leading zero. (Triangular numbers are those that fit the formula n(n+1)/2, like 1, 3, 6, 10, 15.)

I have also found a 3-digit perfect square, a 3-digit triangular number and a 4-digit perfect cube that between them use 10 different digits, with no leading zero.

What are my two 4-digit numbers?

WIN £15 will be awarded to the sender of the first correct answer opened on Wednesday 20 July. The Editor’s decision is final. Please send entries to Enigma 1651, Âé¶¹´«Ã½, Lacon House, 84 Theobald’s Road, London WC1X 8NS, or to enigma@newscientist.com (please include your postal address).

Answer to 1645 Neighbourhood watch: the house number is 32 The winner Alan Beasley of Leominster, Herefordshire, UK

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