perplexus.info :: Just Math : So many quintuplets...

So many quintuplets... (Posted on 2011-03-17)

Determine the total number of quintuplets (A,B,C,D,E) of positive integers such that A<=B<=C<=D<=E<=N. Both analytic and software solution for N=1, 2, ...9,10,...N required.

Submitted by Ady TZIDON

Rating: 4.0000 (3 votes)

Solution: (Hide)

My recursive formula for f(n): f(1)=1; f(n)=f(n-1)*(f+4)/(n-1)

See also excellent presentation and solution by Charlie.

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

Subject	Author	Date
re: solution + spoiler	Ady TZIDON	2011-03-17 18:34:07
Solution	Math Man	2011-03-17 17:32:03
solution	Charlie	2011-03-17 13:31:16

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