

A059775


From solution to a counting problem.


0



0, 24, 120, 360, 824, 1664, 2992, 5000, 7848, 11808, 17024, 23888, 32576, 43432, 56816, 73136, 92616, 115872, 143104, 174928, 211808, 254312, 302680, 357832, 420136, 490232, 568664, 656360, 753496, 861376, 980232, 1111016, 1254504
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OFFSET

0,2


LINKS

Table of n, a(n) for n=0..32.
Emeric Deutsch, Murray S. Klamkin and Denis Constales, Solution to Problem 10540: Counting the Solutions, Amer. Math. Monthly, 108 (Feb. 2001), 172173.


MAPLE

[seq(n*(n1)*(n^2n1) + 4*add(floor(n/k^2)*phi(k), k=2..floor(sqrt(n)))  2*add(floor(n/k)^2*phi(k), k=2..n), n=2..30)];


CROSSREFS

Sequence in context: A114200 A229567 A069074 * A052762 A217056 A099317
Adjacent sequences: A059772 A059773 A059774 * A059776 A059777 A059778


KEYWORD

nonn


AUTHOR

N. J. A. Sloane, Feb 21 2001


STATUS

approved



