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A102448
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a(n) = number of ways to write n = k^2 * j, j <= k, GCD(k,j) = 1, j and k = positive integers.
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4
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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, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 2, 0, 0, 0, 0, 0
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,100
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COMMENTS
| Sum_{n>0} a(n)/n = 2.
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EXAMPLE
| a(18) = 1 because 18 = k^2 * j, j <= k, GCD(k,j)=1, in one way: k=3, j=2.
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MATHEMATICA
| t = Sort[ Flatten[ Table[ If[ GCD[j, k] == 1, k^2*j, {}], {k, 11}, {j, k}]]]; Table[ Count[t, n], {n, 105}] (from Robert G. Wilson v Feb 25 2005)
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CROSSREFS
| Cf. A102354, A104021, A104023, A104025.
Sequence in context: A118553 * A102683 A122840 A083919 A063665 A072507
Adjacent sequences: A102445 A102446 A102447 * A102449 A102450 A102451
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KEYWORD
| nonn
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AUTHOR
| Leroy Quet, Feb 23 2005
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EXTENSIONS
| More terms from Robert G. Wilson v (rgwv(AT)rgwv.com), Feb 24 2005
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