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A366663
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a(n) = phi(9^n-1), where phi is Euler's totient function (A000010).
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14
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4, 32, 288, 2560, 26400, 165888, 2384928, 15728640, 141087744, 1246080000, 14758128000, 85996339200, 1270928131200, 8810420097024, 70207948800000, 677066362060800, 8218041445152000, 43129128265187328, 674757689572915200, 4238841176064000000
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OFFSET
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1,1
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LINKS
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FORMULA
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MATHEMATICA
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EulerPhi[9^Range[30] - 1]
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PROG
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(PARI) {a(n) = eulerphi(9^n-1)}
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CROSSREFS
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phi(k^n-1): A053287 (k=2), A295500 (k=3), A295501 (k=4), A295502 (k=5), A366623 (k=6), A366635 (k=7), A366654 (k=8), this sequence (k=9), A295503 (k=10), A366685 (k=11), A366711 (k=12).
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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