perplexus.info :: Numbers : Unconsecutive-summables

Unconsecutive-summables (Posted on 2011-04-14)

[1] Find all positive integers that cannot be written as the sum of 2 or more consecutive positive integers.

[2] Find all integers that cannot be written as the sum of 2 or more consecutive integers.

[3] Find all positive integers that can only be written as the sum of 2 or more consecutive positive integers in one way.

Submitted by Jer

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Solution: (Hide)

[1] Powers of 2.
[2] All numbers can be done this way. For example 4 = -3+-2+-1+0+1+2+3+4
[3] Primes multiplied by powers of 2. i.e. numbers of the form p*2^n.

Comments: ( You must be logged in to post comments.)

Subject	Author	Date
re: possible solution	Jer	2011-04-15 00:22:27
Part 2 (spoiler)	Steve Herman	2011-04-14 20:27:20
possible solution	Dej Mar	2011-04-14 19:38:31

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