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2, 12, 90, 756, 6642, 59292, 532170, 4785156, 43053282, 387440172, 3486843450, 31381236756, 282430067922, 2541867422652, 22876797237930, 205891146443556, 1853020231898562, 16677181828806732, 150094635684419610
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,1
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FORMULA
| G.f.: 1/(1-3*x)+1/(1-9*x). E.g.f.: e^(3*x)+e^(9*x). [From Mohammad K. Azarian (azarian(AT)evansville.edu), Jan 11 2009]
a(n)=12*a(n-1)-27*a(n-2) with a(0)=2, a(1)=12 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Jul 21 2010]
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MATHEMATICA
| Table[3^n + 9^n, {n, 0, 25}]
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CROSSREFS
| Cf. A000051, A034472, A052539, A034474, A062394, A034491, A062395, A062396, A007689, A063376, A063481, A074600 - A074624.
Sequence in context: A174356 A121357 A098926 * A155639 A103882 A003123
Adjacent sequences: A074607 A074608 A074609 * A074611 A074612 A074613
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KEYWORD
| easy,nonn
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AUTHOR
| Robert G. Wilson v (rgwv(AT)rgwv.com), Aug 25 2002
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