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A078429
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Number of k = 1..n for which GCD(k,n) is a cube.
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0
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1, 1, 2, 2, 4, 2, 6, 5, 6, 4, 10, 4, 12, 6, 8, 9, 16, 6, 18, 8, 12, 10, 22, 10, 20, 12, 19, 12, 28, 8, 30, 18, 20, 16, 24, 12, 36, 18, 24, 20, 40, 12, 42, 20, 24, 22, 46, 18, 42, 20, 32, 24, 52, 19, 40, 30, 36, 28, 58, 16, 60, 30, 36, 37, 48, 20, 66, 32, 44, 24, 70, 30, 72, 36, 40, 36
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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FORMULA
| a(n) is multiplicative. G.f. for a(p^n), p a prime, is given by 1/(1+x+x^2)/(1-p*x). a(2^n) = A077947(n), a(3^n) = A077834(n). a(p) = p-1, a(p^2) = p*(p-1), a(p^3) = p^3-p^2+1, a(p^4) = (p-1)*(p+1)*(p^2-p+1), ...
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CROSSREFS
| Cf. A061020.
Sequence in context: A028913 A185048 A054929 * A171751 A124676 A076249
Adjacent sequences: A078426 A078427 A078428 * A078430 A078431 A078432
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KEYWORD
| mult,nonn
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AUTHOR
| Vladeta Jovovic (vladeta(AT)eunet.rs), Dec 29 2002
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