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A015506
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a(1) = 1, a(n) = Sum_{k=1}^{n-1} (5^k - 1)/4 a(k).
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10
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1, 1, 7, 224, 35168, 27501376, 107447876032, 2098671914657024, 204950003169660992768, 100073397447688408870744576, 244319893042568615235897903058432, 2982420752607212448380293251367177293824
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OFFSET
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1,3
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LINKS
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FORMULA
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MATHEMATICA
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a[n_, m_]:= a[n, m]= If[n<3, 1, (m^(n-1)+m-2)*a[n-1, m]/(m-1)];
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PROG
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(Magma) [n le 2 select 1 else ((5^(n-1)+3)/4)*Self(n-1): n in [1..15]]; // Vincenzo Librandi, Nov 12 2012
(SageMath)
def a(n, m): return 1 if (n<3) else (m^(n-1) + m-2)*a(n-1, m)/(m-1)
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CROSSREFS
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Sequences with the recurrence a(n) = (m^(n-1) + m-2)*a(n-1)/(m-1): A036442 (m=2), A015502 (m=3), A015503 (m=4), this sequence (m=5), A015507 (m=6), A015508 (m=7), A015509 (m=8), A015511 (m=9), A015512 (m=10), A015513 (m=11), A015515 (m=12).
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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