m = k^2 *j, j<=k, GCD(k,j)=1
Leroy Quet
qq-quet at mindspring.com
Sat Feb 19 18:17:28 CET 2005
Let a(m) be the number of ways that (ie. the number of (k,j)'s where)
m = k^2 *j,
j <= k,
GCD(k,j)=1,
j and k= positive integers.
So we have the sequence:
{a(m)}: 1,0,0,1,0,0,0,0,1,0,0,0,0,0,0,1,0,1,0,0,0,0,0,0,1,0,0,...
(Not every term is 0 or 1. a(100) = 2.)
And we can also have the sequence, {b(n)}, of m's where a(m) >= 1:
{b(n)}: 1, 4, 9, 16, 18, 25, 36, 48, 49, 50,...
Neither sequence is in the EIS.
I know these sequences might seem a tad arbitrary.
But here is a puzzle (for fun) which might somewhat justify the
a-sequence:
Evaluate the sum:
sum{m=1 to oo} a(m)/m.
(I'll give the answer in a few days if no one gets it sooner. But someone
surely will get the {somewhat surprising} answer soon, since this puzzle
is not extremely difficult.)
thanks,
Leroy Quet
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