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A074607
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a(n) = 3^n + 6^n.
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2
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2, 9, 45, 243, 1377, 8019, 47385, 282123, 1686177, 10097379, 60525225, 362974203, 2177313777, 13062288339, 78368947065, 470199333483, 2821152954177, 16926788584899, 101560344088905, 609360902271963, 3656161926847377
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OFFSET
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0,1
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LINKS
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FORMULA
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G.f.: 1/(1-3*x) + 1/(1-6*x).
E.g.f.: exp(3*x) + exp(6*x). (End)
G.f.: G(0), where G(k)= 1 + 2^k/(1 - 3*x/(3*x + 2^k/G(k+1) )); (continued fraction). - Sergei N. Gladkovskii, Jul 22 2013
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MATHEMATICA
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Table[3^n + 6^n, {n, 0, 25}]
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PROG
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(SageMath) [3^n+6^n for n in range(41)] # G. C. Greubel, Jan 14 2024
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CROSSREFS
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Cf. A000051, A007689, A034472, A034474, A034491, A052539, A062394, A062395, A062396, A063376, A063481, A074600..A074624.
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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